Ben 10 Wiki
Ben 10 Wiki
34497a3fe0ef52949a1ba8e99894ed69 This article belongs to the Classic Continuity

Side Effects is the twelfth episode of the first season of Ben 10, and the twelfth episode overall.


Ben catches a cold and the symptoms wreak havoc on his alien heroes. To make matters even worse, he has to battle a villain who controls insects.[note 1]


Side (33)

Clancy's debut

Two construction men are busy knocking down an old, abandoned apartment building, when a mysterious man named Clancy appears from the intact parts of it and tells them to leave. They retort that the building was condemned by the city's local councilwoman, Liang, and will be torn down. This angers Clancy, who sends swarms of insects after the two to make them flee, revealing his unnatural ability to control and communicate with insects on the telepathic level.

In another part of the city, in the Rustbucket, Max and Gwen are in hot pursuit of a robber in a hot rod, speeding through the streets trying to make off with his score confident they'll never catch them. However, Gwen spots something faster on the road: Ben, as Upgrade, possessing a motorcycle. The motorcycle is small and nimble enough to cut corners, swerve past people on the sidewalk, and slide underneath passing trucks, eventually managing to get right behind the crook's car. Upgrade blasts open the trunk full of money and slices the car's tire to stop it in a controlled crash. Upgrade cheekily reveals to the robber that no one was in the driver's seat by giving him a taste of his exhaust smoke before rolling away as the police arrive. Upgrade parks directly behind an ice cream truck and, feeling that he deserved a reward, abandons ship and hides inside it. Once Max and Gwen arrive on the scene, Gwen quickly deduces Ben is inside the ice cream truck and find him there, now detransformed, sniffling and sneezing profusely. Max takes him back to the RV and takes his temperature, to which it is obvious that Ben has officially come down with a summer cold.

Side (267)

Ben is sick

While Ben mopes about having a cold, Max assures him that all he needs is his famous San Ju Yen Pien cold remedy. He takes them on a walk to the city's Chinatown, where he can pick up the ingredients (which do not bode well to Ben because of the smell). A parade is happening in the Chinatown square and Councilwoman Liang starts to make a speech of appreciation for the support of her redevelopment program. As she talks, wasps exponentially appear in the air, until the entire crowd is swarmed. Clancy arrives on a raft of insects, declaring his hatred for Liang at trying to tear down his apartment building. He kidnaps her back to his house. Ben tries to save her by going alien and turns into Wildmutt, but his abilities are greatly hindered and only succeeds in running headfirst into everything around him. Max concludes that Wildmutt's sensory gills are clogged up with snot because of Ben's cold, so without the use of his sense of smell, Wildmutt is left at a grave disadvantage without any way of telling where he's going. Gwen decides to drive him by getting onto his back, but it proves disastrous when Ben gets her trapped under a box filled to the brim with fireworks. Things only go from bad to worse when the wasps cut one of the lantern strings from above, which catches fire and ignites a path straight to Gwen, leaving her at the mercy of the imminent detonation of live pyrotechnics.

Side (466)

Ben's cold affects Wildmutt's abilities

When the fuse to the fireworks is ignited by the approaching fire, Max saves Gwen in the nick of time with a cart filled with chicken dumplings, but Ben is still stuck running around blind as Wildmutt. Eventually, the Tennysons retreat to the RV, where Ben is forced to take a dose of the cold remedy, which proves to taste as nasty as it smells. However, the medicine proves integral since it's become painfully clear that Ben's cold will remain even in alien form, and it will have all kinds of ghastly effects on his aliens as it has with Wildmutt. Meanwhile, Gwen researches where Clancy's apartment might be, and she is able to isolates a location while Ben secretly hides the remedy in a drawer at the back of the RV.

Inside the creepy, rickety apartment, Clancy has Liang completely at his mercy while she is engulfed in a swarm of Black Widows. He explains what the apartment building means to him, saying his grandfather built it with his own two hands from the ground up and he grew up in it with all his little friends. Clancy's family is now each and every one of the bugs that inhabit the building and will not take kindly to anybody daring to evict "them".

Side (907)

Four Arms accidentally destroys Clancy's home

The Tennysons arrive and explore the building as a group. They find nothing at first until they are beset with an enormous "mega bug" lumbering toward them, but this "mega bug" turns out to be Ben who transformed Four Arms as a prank. They then hear Liang's cry for help on the floor above them and Four Arms grabs Max and Gwen, preparing to jump to the floor above. However, the effects Ben's cold has on Four Arms becomes grossly apparent as he has developed smelly hives on his armpits. Nevertheless, they find Liang on the floor above, unable to move due to still being covered in the deadly black spiders. While the gang looks for a way to help her, Four Arms incidentally sneezes on her. As gross as it is, his snot washes away the spiders, and she is safe. Clancy appears and does not take kindly to the trespassers. He sends off swarms of bugs to fight off the gang, such as a cloud of red bugs able to punch through solid wood that leave a mark on Four Arms and Gwen almost falls through the floor when termites emerge from right under her. Ben tries to make his move, but Clancy summons a swarm of fire ants from all sides and when they're all over Four Arms, he itches out of control from being bitten all over. He jumps around and swerves all over the place trying to get rid of them, accidentally slamming into the building's beams until he completely compromises the last of the building's old and decrepit structural support. With the building coming down around them, Clancy makes a shield of wasps while Four Arms shields everybody else with his body as the place totally collapses.

With Clancy's apartment building completely destroyed, Four Arms' efforts ensure everybody is left unscathed, but collapses from exhaustion (and his cold) before the Omnitrix times out. Thanks to Clancy's "friends", he also emerges unscathed. Distraught over the loss of his apartment building and all the bugs that perished with it, Clancy declares revenge on the entire city and disappears in a wasp-nado. Councilwoman Liang is overwhelmed by the weirdness and confused by the disappearance of Four Arms, saying that she wanted to thank him for saving her from the spiders. Ben simply tells her that he'll let him know and Max tells her to find her way back home from there. With that resolved, Ben asks where they think Clancy may have crawled off to and Max deduces that the city's local nuclear power plant is the only way anyone could exterminate a whole city. As the Tennysons drive over to it, Ben just narrowly avoids another dose of that foul medicine and Gwen uses her laptop to research the best possible solution to fight off a guy with power of insects. To that end, she notifies Ben that without the bare minimum of a second ice age or a truckload of pesticide, the best method to dealing with them would be with extreme heat.

Upon arriving at the plant, the Tennysons are walking through a dark hallway when a loud alarm sounds followed by an announcement regarding the current condition of the reactor core. Once they get inside the control room, they discover that Clancy has smashed the reactor's controls and is planning to let its temperature rise to super-critical levels and if it can't be stopped, the resulting nuclear fallout will poison the whole city. With all the remote controls smashed, Max declares that they'll have to shut down the reactor core manually with the emergency override system just outside of it. Just then, Clancy appears and shows just how much he's looking forward to the place going nuclear with a "suit" of hundreds of cockroaches and informs them that with it, he will be the only one unaffected by the meltdown due to the cockroach's invulnerability to radiation. Ben successfully turns into Heatblast like they initially planned, although, he is strangely blue. Nonetheless, he sends Max and Gwen to shut down the reactor while he fights off Clancy. He holds the upper hand against Heatblast while he sends murder hornets after Max and Gwen. Ben tries fighting back but discovers that he has no fire power as long as he's sick. With only five minutes before the meltdown, Max and Gwen make it to the end of the hallway as they are pursued by the hornet swarm and Gwen defeats them all with a firehose. Heatblast is losing hard against Clancy without any of his fire until he discovers the amazing (and somewhat literal) truth behind how his cold affects Pyronites; instead of completely hindering his powers, his cold inverts them entirely, thus granting him power over cold and ice instead of fire.

Max and Gwen make it to the reactor core chamber with only a minute to turn the tide, but Ben gains the upper hand with his newly discovered cryokinesis. However, the ice manages to slow Clancy down, but Ben still doesn't have the manpower to defeat him. Clancy tackles him into the core chamber while Gwen is struggling to hold off the bug army surrounding them with a broom so Max can stop the meltdown. Gwen is perplexed to see Heatblast with cryokinesis, and Heatblast simply responds that for some aliens, getting a cold is no longer a mere expression. Unfortunately, things seem hopeless as Max discovers that the manual override has overheated beyond use. Clancy charges at Heatblast again, but Heatblast flash-freezes him into a giant block of ice and finally defeats him. With time running out, Heatblast is struck with one last idea. He unleashes the full power of his ice ray on the core, gradually encasing it in ice. The countdown to the meltdown narrowly reaches 0, but Heatblast's determination prevails as the core is completely frozen solid just in time and its temperature is restored to stable levels. Ben is hailed as a hero, but his cold still demands some hot chocolate now that the crisis has been averted.

Side (1297)

Heatblast gains cryokinetic abilities and saves the day

The Tennysons decide to leave Clancy on ice and drive away and Ben recovers, as the resulting steam from his blizzard blast on the reactor knocked away the last of his cold. Just when everybody is rejoicing about how well things worked out, Gwen prepares to stomp on a cockroach she finds on the floor. However, the Rustbucket is suddenly swarmed with bugs. Clancy steps in the RV, having somehow thawed out pretty quick and ready to enact his revenge on the Tennysons. He attacks Max while Gwen fends off the bugs with a fire extinguisher and Ben is unable to transform while the Omnitrix still has yet to recharge. In their struggle against an army of bugs, Gwen gives Ben an idea. He runs to the back of the RV and pulls out the San Ju Yen Pien remedy he hid, its pheromones and strong stench attracting all the bugs to it as it overshadows Clancy's telepathic control over them. He throws it out the window into the river beside them. All the bugs chase after it, out of the RV, leaving Clancy defenseless. Max gives him a good knockout punch and Clancy is finally defeated for good. Max heads back inside to dial up the police and Gwen sneezes, groaning at the realization that she now has the cold. In Ben's eyes, everything's worked out great.

Noteworthy Events[]

Major Events[]

  • Team Tennyson meets Clancy.
  • It was revealed that when Ben gets sick, his aliens get sick as well, affecting them in different and unpredictable ways.

Character Debuts[]



Aliens Used[]


The Upgrade bike catches up to the robber's car.
Upgrade: Hey!
Robber: (hearing him behind) Huh?
Close enough, Upgrade uses his eye to blast a laser at the trunk, blowing it clean off. Stolen bills come flying out of the trunk.
Upgrade: Some people just can't hang on to their money.
Out of the side of his front wheel, Upgrade forms an energy spike. He speeds up to the car's back wheel and drives the spike into it, causing the car to spin out of control and safely crash into some parked cars. Upgrade drives himself up to the reeling driver to show himself, no driver and all.
Robber: No way!
Upgrade burns rubber, pushing exhaust in the robber's face. He runs off once police cars start coming in the distance.

Max and Gwen watch the robber get arrested.
Robber: Look, I'm telling ya. Tha-that motorcycle, i-it was driving itself!
Max: (to Gwen) Where's Ben?
Gwen: Long chase, hot day, I'm thinking...?
She motions to the ice cream truck right behind her.

Max: Well, 101. Sorry, Ben, it's official: you have a summer cold.
Gwen: Maybe from now on you'll think twice before having snack time inside an ice cream truck!
Ben feels a sneeze winding up. He grabs some blue clothing and uses it to rub his nose.
Gwen: Hey! That's my new blouse!
He sneezes right into it. His voice is stuffy.
Ben: Maybe from now on you'll think twice about leaving your new clothes just lying around!
Gwen goes back to pulling various things out of a box.
Gwen: Cold tablets, decongestant, cough suppressant, hospital mask...
Ben: (sitting up) I don't need all that junk.
Gwen: They're not for you, dweeb! They're for me! Once a bug like that gets out, there's no stopping it!
Ben: (to Max) Why don't you just lock me away in some closet somewhere until I'm better?
Gwen: (gasps) Can we, Grandpa? Pretty please?!

At Clancy's apartment, spiders crawl up Liang's dress.
Liang: (shuddering) Please...don't hurt me!
Clancy steps out from the shadows.
Clancy: Mmmm, black widows... You shouldn't make any...sudden moves.
Roaches watch Clancy as he continues talking,
Clancy: Our grandfather built this building. We grew up here! Just me and my little friends... They are the only ones who understand, and no one is evicting us!

Four Arms: You want to be king? Get ready to be crowned!
Four Arms starts charging toward Clancy. His eyes light up and thousands of red bugs swarm Four Arms' feet and travel up his legs. He suddenly starts hopping on one foot and scratching his infested leg.
Four Arms': Aaaagh! Aaants in my paaants!

Gwen: Wow, listen to this! Ants can lift 10 times their own body weight, grasshoppers can leap 100 times their length, and cockroaches can hold their breath for over an hour!
Ben: We don't need their résumés, we need to know how to squash them!
Gwen: Duh! I'm saying insects are pretty tough little suckers! Short of another ice age or a tanker full of pesticide, looks like holding a "bug barbeque" is our best option!
Ben: (gripping the Omnitrix) And I know just the chef...

Heatblast: That's it. Time to turn up the Heatblast around here!
Heatblast cups his hands and throws them forward, but nothing shoots out. He instead sneezes.
Heatblast: Hey, what happened? You should be a bunch of briquettes by now... My cold! it froze my flames!

Gwen: Grandpa, I can't hold these bugs off much longer!
Plant Intercom: Meltdown in 30 seconds.
The swarm quickly stops as Heatblast freezes them in midair. He then rides the frozen end of his projectile down to the ground.
Heatblast: Somebody call...for a hero?!
Gwen: I don't get it. Since when are you an automatic ice cube maker?
Heatblast: Heheh. I guess for some aliens, 'getting a cold' isn't just an expression!

Naming and Translations[]

Language Name Origin
Dutch Bijwerkingen Side Effects
French Effets Secondaires Side Effects
German Die Supermedizin The Supermedicine
Hungarian Mellékhatások Side Effects
Italian Effetti Collaterali Side Effects
Polish Efekty Uboczne Side Effects
Portuguese (Br) Efeitos Colaterais Collateral Effects
Romanian Efecte Secundare Side Effects
Russian Бен Простудился Ben Caught A Cold
Spanish (HA) Efectos Secundarios Side Effects
Spanish (Spain) Efectos Secundarios Side Effects
Turkish Yan Etki Side Effect


Voice Actor Role(s)
Tara Strong Ben Tennyson
Meagan Smith Gwen Tennyson
Paul Eiding Max Tennyson
Dee Bradley Baker Wildmutt
Steve Blum Heatblast
Richard McGonagle Four Arms
Rosalind Chao Councilwoman Liang
Nicholas Guest Clancy
Nancy Linari Computer Voice


  • Upgrade's motorbike bears a great resemblance to a 1983 Honda XL500 trail bike from Street Hawk, a show about a cyborg motorcyclist who stops criminals.
  • The bank robber was designed by and modeled after Dave Johnson.[DJ 1]
  • The vehicle used by the thief at the beginning of the episode resembles a 1970s Oldsmobile Cutlass convertible.


  • Joe is first voiced by Steve Blum at the beginning of the opening scene, but when Clancy shows himself, Dee Bradley Baker voices Joe instead, with Steve Blum voicing Bob. Joe is voiced by Steve Blum again when Clancy uses his wasp swarm to grab him.
  • In many shots, the Omnitrix's dial faces the wrong way.
  • When Max first talks about his San Ju Yien Pien remedy, his hair has inverted colors.
  • When the Tennysons split up the hallway as they're exploring Clancy's building, Max walks off onto the wall as if it were the floor.
  • When Four Arms says "Oops!", his mouth is open but does not move.
  • The nuclear reactor has no employees and no one to stop the Tennysons from coming in.
  • No one requires radiation protection, despite direct exposure to a nuclear core.
  • In one shot when Ben tries to fend off the wasps in the Rustbucket, the Omnitrix's dial is white and green instead of grey and green.


Side (92)
  • During Upgrade's chase scene, one of the bystanders who moves out of Upgrade's way wears clothes very similar to Ben's usual attire in Alien Force and Ultimate Alien.
  • When Max tells Ben his temperature, it is on the Fahrenheit scale. In the Brazilian dubbing, the temperature is in Celsius due to the country being the only one to use this scale.
  • The plot lightly mirrors the 1992 horror film Candyman.


  1. The original synopsis provided on the Cartoon Network website erroneously reads: "Ben catches a cold and the symptoms wreak havoc on his alien heroes. To make matters even worse, he has to battle a creature made from cockroaches."[CN 1]


Crew Statements[]

Kersti Myrberg[]

Dave Johnson[]

Cartoon Network[]

Ben 10 Episodes