Here I'm going to show every first and last line/word for each alien (I won't be counting the reboot as their last line,but I'll make an exception to the reboot exclusive aliens, and I won't be counting the shouting of the names as the first/last lines) and I won't count ultimates,fusions,etc, I'll be referring to the first lines as 'F',and the last lines as 'L' , do note that I'm going by production order not airing order or chronological order
-Heatblast F: "AHHHHH , I'M ON FIRE, I'M ON FIRE!! (And Then There Were Ten)
L : "What?" (Stuck on You)
-Wildmutt F: Animalistic roars and noises (And Then There Were Ten)
L: Animalistic roars and noises (Fight at the Museum)
-Diamondhead F: "I don't know, but I bet it's gonna be cool" (And Then There Were Ten)
L: "SERIOUSLY?!!?" (Malgax Attacks)
-XLR8 F: "Yup. Hey,check this out!" (And Then There Were Ten)
L: "Well that turn of events is about to kick your butt " (A New Dawn)
- Grey Matter F: "Aw man,another red card!" (Washington B.C)
L: "Rewire this cutling here and..." (It's A Mad, Mad,Mad Ben World part 2)
- Four Arms F: "Let's wrestle!" (Washington B.C)
L: "Sweet,this changes things " (Universe Vs Tennyson)
- Stinkfly F: "Gotcha" (Washington B.C)
L: "Less quipping, more whistle fighting !" (Of Predators And Prey part 2)
- Ripjaws F: "You wanna mess with a monster? Try me on for size " (The Krakken)
L: "I think I'm gonna cry, or maybe I'm already crying, I can't tell " (The Ballad of Mr Baumann)
- Upgrade F: "Your cash request has been denied" (Permanent Retirement)
L: "Grandpa, you've got to evacuate Bellwood!" (The Final Countdown)
- Ghostfreak F: "Loser! Loser! HA HA HA!" (Permanent Retirement)
L: "Hey" (A New Dawn)
- Cannonbolt F: "Uhhh,woah, guys what am I?" (The Big Tick)
L: "Oh man, she doesn't give up " (No Honor Among Bros)
- Wildvine F: "Beats me, I never went him before" (Camp Fear)
L: "Is that it?!" (Breakpoint)
- Spitter F: ............spits intensify (Ben 10,000)
L: .........spits intensify (Ken 10)
- Buzzshock F: "Dad,I had him!" (Ken 10)
L: "Argit!" (Cough It Up)
- Arctiguana F: "I don't name-....um I don't know" (Ben 10,000)
L: "Hokestar!" (Collect This)
- Blitzwolfer F: "And why the Omnitrix isn't on my wrist anymore, but how'd I go alien?" (Benwolf)
L: "I'm not really a dog you know " (The Secret of Dos Santos)
- Perk Upchuck F: "What's this thing supposed to do?" (The Visitor)
L: "Well,at least he can dish it out as well as he takes it!" (No Honor Among Bros)
- Snare Oh F: "The mummy? Oh great " (The Return)
L: "Rook, the arms!" (The Secret of Dos Santos)
- Frankenstrike F: "Electromagnetic body, sweet " (Be Afraid of the Dark)
L: "Strike 3!" (The Color of Monkey)
- Ditto F: "Another alien!? Ok let's see what you can do " (Divided We Stand)
L: "Can't see how that's possible" (Universe Vs Tennyson)
- Eye Guy F: "Ok Animo,science class is cancelled " (Secret of the Omnitrix)
L: "You'll thank me for it later. Jonesy!" (From Hedorium to Eternity)
- Way Big F: "Woah , check me out, I'm not just big ,I'm WAY BIG!" (Secret of the Omnitrix)
L: "Oh,that was so funny I forgot to laugh " (From Hedorium to Eternity)
- Swampfire F: " Ew,what is that smell?Is that me?" (Ben 10 Returns part 1)
L: "Maybe you're too crazy to get out of here, but I've got Gwen and Rook waiting for me " (Weapon XI part 2)
- Echo Echo F: " Got him" (Ben 10 Returns part 2) L: "Don't worry, we'll get you back to your group" (Tummy Trouble)
- Humungousaur F: "YES! Guess what time it is? IT'S HERO TIME!" (Ben 10 Returns part 2)
L: "Don't expect me to thank-" (Stuck on You)
- Jetray F: "Get off me!" (Everybody Talks About the Weather )
L: "Wonder if he can absorb THIS!" (Couples Retreat)
- Big Chill F: "He would be if he were alone,but he's with us" (Kevin's Big Score)
L: "Being frightened by a zombie clown doesn't turn you into a zombie clown. So much for that theory " (Something Zombozo This Way Comes)
- Chromastone F: "That's not going to work,I'm a conductor!" (All That Glitters)
L: "I thought it" (A New Dawn)
- Brainstorm F: "Ugh,I'm not Jetray, I'm a sea food platter, mmm and a pently one possessed of a highly advanced intellect,and perhaps I should assign this new life form a more appropriate name,what say BRAINSTORM!" (Pier Pressure)
L: "You wanna play superhero?You want all the glory? Fine,you can have it" (The Vengers)
- Spidermonkey F: "Woah,woah,woah! Easy does it,I'm trying to help " (Be-Knighted)
L: "NO!" (Cough It Up)
- Goop F: "You know this is cool" (The Gauntlet)
L: "But that's not-" (It's a Mad,Mad,Mad Ben World part 1)
- Alien X F: "Seconded! Water stopping motion carried!" (X = Ben + 2)
L: "Told ya" (Universe Vs Tennyson)
- Murk Upchuck F: "Everybody get together. On three. One,two,THREE!" (War of The Worlds part 1)
L: "Hey! Quiet down here!" (Tummy Trouble)
- Nanomech F: "I like it!" (Alien Swarm)
L: "Oh man,I forgot about the security scanner. Oh please, oh please, oh please!" (The Ultimate Heist)
- Lodestar F: "Oh man,this is no time to shake down a new guy" (Simple)
L: "Nerd? Really? Face it sir dunce-a-lot , you're not getting away with him" (Return to Forever)
- Rath F: "You wanna fight me Kevin Levin? LET'S GO!" (Con of Rath)
L: " *translated* Let me tell you something...,Rath will fall...." (The Secret of Dos Santos)
- Water Hazard F:"I was going for Big Chill, but I still think I can cool you off. First,some nice cold water. Then, I'll absorb the moisture from the air!" (Hero Time)
L: "No sweat,I've got everything under-OW!" (Bengeance Is Mine)
- AmpFibian F: "Yeah,problem is, Aggregor won't give up;he'll come after us. And when he does,you had better be ready!" (Fused)
L: "Send us the bill!" (The Rooters of All Evil)
- Armodrillo F: "Need a hand,captain? (Hero Time)
L: "Can't you keep your mouth shut for one minute?" (The Secret of Dos Santos)
- Terraspin F: "If you think for one second that Kevin wouldn't drain you dry...." (Absolute Power part 1)
L: "And I say: let's start with something less risky" (Rook Tales)
- NRG F:"Ah,can I catch a break?" (The Forge of Creation)
L: "Oh for the love of....This again? (Rad Monster Party)
- Fasttrack F: "I thought that would go diffdifferently " (Solitary Assignment)
L: "How ya doin" (The Beginning of The End)
-Clockwork F: "Face it Nesmith,your time is up" (Catch A Falling Star)
L: "Get ready,get set" (It's A Mad, Mad ,Mad Ben World part 2)
- ChamAlien F: "OVERKILL! Well? Well? Too soon?" (Prisoner 775 Is Missing)
L: *exception as he has no other last line* "CHAMALIEN!" (Night of The Living Nightmare)
- Shocksquatch F:"AUUH! Woah,this is unexpected " (Heroes United)
L: "Ugh,how am I supposed to save them if I can't even save myself?" (The Most Dangerous Game Show)
- Eatle F: "Woah,my eyes are bigger than my stomach. I need a plan B" (Enemy of My Frenemy)
L: "I turned into aliens I didn't even know I had,then I got Eatle and, well...." (Let's Do The Time War Again)
- Juryrigg F: "Awesome kind!" (The Eggman Cometh)
L: "Give me a break! It was the best I could do with the parts I had" (It's A Mad, Mad, Mad Ben World part 1)
- Feedback F: "Oh yeah, Feedback!" (The More Things Change part 1)
L: "You wanted your very own big bang!" (A New Dawn)
- Bloxx F: "Whoa,who's this guy?" (The More Things Change part 1)
L: "Not quite yet" (It's A Mad, Mad, Mad Ben World part 2)
- Gravattack F: " Who's this?" (A Jolt from The Past)
L: "Okay,everyone, hang on" (Malgax Attacks)
- Crashhopper F: "Woah,new alien. Cool! I wonder what I can do" (It Was Them)
L: "Solid Plugg?" (Breakpoint)
- Ball Weevil F: "Woah,this is a new one. Uh-um what can it do? I gotta have something for me going other than the power of cuteness " (Of Predators And Prey part 1)
L: "That'll usually work" (The Most Dangerous Game Show)
- Walkatrout F: " I'm going to call that a no" (Outbreak)
L: "I'm here!" (The Final Countdown)
- Pesky Dust F: "I'm going " (Outbreak)
L: "Let's just say I know the cure for entertainment " (The Most Dangerous Game Show)
- Mole-stache F: "Oh come on! What is the point of this guy ?He's totally useless!" (Outbreak)
L: "I guess you aren't quite so Vilgax-y yet" (A New Dawn)
- The Worst F: "Aw,this guy's the worst!" (Outbreak)
L: "IT BURNS!!" (It's A Mad, Mad,Mad World part 1)
- Kickin Hawk F: "Omnitrix is fixed,and thanks to you,I got me a new alien " (Outbreak)
L: "We're here from the network" (The Most Dangerous Game Show)
- Toepick F: "STAY AWAY FROM ME!!" (Something Zombozo This Way Comes)
L: "Got him. Okay now,this isn't going to be pretty" (Cough It Up)
- Astrodactyl F: "Alright! I always wanted to be one of these um....whatever they are" (While You Were Away)
L: "Come on Clyde,land that thing" (Clyde Five)
- Bullfrag F: "Princess!" (The Frogs of War part 2)
L: "I was trying to stop a disaster not cause one" (It's A Mad, Mad, Mad Ben World part 1)
- Atomix F:"I'm no bug,I am uhh..." (For A Few Brains More)
L: "NOT AGAAAAAAIN!" (Malgax Attacks)
- Gutrot F: "Ok who's this?" (Animo Crackers)
L: "Uh listen , I don't want to say I told you so,but uh,I TOLD YOU WE SHOULD'VE LEFT!" (Vreedlemania)
- Whampire F: "Hobble? Sorry, I-" (The Vampire Strikes Back)
L: "Release him" (The End of An Era)
- Overflow F:"Here we go!" (Waterfilter)
L:"You might be right grandpa " (Fear The Fogg)
- Gax F: "HAHA! COOL!" (Omni-Tricked part 1)
L:"Wow, I usually just go with the flow. Maybe there really is something to this; having control " (Omni-Tricked part 3)
- Shock Rock F: "Ha! I know exactly what I've done!" (The 11th Alien part 1)
L: "Oh,what? It's over?" (Alien X-tinction)
- Slapback F: "Who's the man? Not you cuz you're alien? Who's the alien?" (Omni-Copped)
L:"There has to be something we can do" (Ben Gen 10)
- Bashmouth F: "This big guy? I think I'll call him: BASHMOUTH!" (Introducing Kevin 11)
L: "More like the ultimate doofus!" (Ben 10 Versus The Universe : The Movie)
- Surge F:"Wow! Feels like I'm having a power surge . Wonder what we can do. TAKE THAT! Uh,TAKE THAT! What gives?" (Ben 10,010)
L:"HAVE IT YOUR WAY!" (Ben 10,010)