Malefactor

Malefactor is the fifteenth episode of Ben 10: Omniverse.

Plot
The episode starts with Ben and Rook walking to the Olde Bellwood Days. Armodrillo quickly changes into Big Chill while Slamworm transforms into a Psycholeopterran named Hypnotick, a rare and almost extinct predator of the Necrofriggians. Big Chill then remembers when he first saw one.

A flashback appears, with 11 year old Ben, Gwen, and Grandpa Max visit Mt. Rushmore for a surprise. There, Max gives them special glasses and shows them an injured Psycholeopterran, saved by Plumbers from smugglers. Suddenly, the Plumber base alarm goes off and Ben, Gwen, and Max go to solve the problem. Malware surfaces and attacks the Plumber base. Ben turns into XLR8 to keep Malware busy while gwen saves the plumbers from danger, but the Omnitrix times out and Ben is about to be killed by Malware. Then, Max attacks Malware with a Tachyon Cannon, which disrupts his structure. However, Malware regenerates and absorbs the Tachyon Cannon, mutating into his dinosaur like form. He is about to use it on humans, but the ray is blocked by Feedback. Feedback fights Malware for some time. Meanwhile, Khyber successfully obtains the Psycholeopterran DNA. Malware then tells Ben that he already got what he came for and leaves. Max realizes it was the Psycholeopterran, but finds the creature as it is.

Coming back to the present, Big Chill tries to escape from Hypnotick. After some time, Ben realizes that Khyber and his dog are just wasting his time. Meanwhile, Rook is taking on Khyber. While talking to him, Rook finds that they have come for the Proto-TRUK. Ben reaches the TRUK as Heatblast, and is freaked out seeing Malware. Ben decides to finish Malware and turns into Humungousaur, but Malware sends a gas tank towards a school bus. Ben goes to save the school bus and Malware escapes. Rook reveals that the Proto-TRUK's memory core was destroyed, along with the auxiliary power systems.

Major Events

 * Brainstorm makes his Omniverse debut.
 * Mt. Rushmore makes its first appearance as an active Plumber base.
 * Hypnotick makes her first appearance.
 * It is revealed how Malware got into his current form.
 * Ben encounters and fights Malware for the first time in 5 years.

Omnitrix Alien Debuts

 * Brainstorm (Omniverse debut)

Nemetrix Alien Debuts

 * Hypnotick (first appearance)

Present Characters

 * Ben Tennyson
 * Rook Blonko
 * Natalie Alvarez (first appearance)
 * Madison (cameo)
 * Mr. Baumann (Ben's dream)
 * Pakmar (Ben's dream)
 * Julius (cameo)

Past Characters

 * Ben Tennyson (11 years old)
 * Gwen Tennyson (11 years old)
 * Max Tennyson (61 years old)
 * Plumbers
 * Jerry
 * Molly Gunther
 * Smuggled Psycholeopterran (first appearance)

Present Villains

 * Khyber
 * Khyber's Dog
 * Malware

Past Villains

 * Khyber
 * Malware

By 16 year old Ben

 * Brainstorm (first re-appearance)
 * Stinkfly (cameo)
 * Wildmutt (cameo)
 * Spidermonkey (cameo)
 * Humungousaur (x3; third time was cameo)
 * Heatblast (x2; first time was accidental transformation, intended alien was Humungousaur)
 * Armodrillo
 * Big Chill

By 11 year old Ben

 * XLR8
 * Feedback

By Zed

 * Buglizard
 * Crabdozer
 * Slamworm
 * Hypnotick (first appearance)

Errors

 * When Ben and Rook enter the Olde Bellwood Days, the sign says Olde Belwood Days.
 * In the flashback, immediately before Ben selects XLR8, the button on the Omnitrix is on the wrong side.
 * In the same scene when Ben activates the Omnitrix, the dial doesn't open up only the core.
 * Also in that scene, the Omnitrix's core angle is off. It's upright when it should be somewhat tilted on its right (otherwise, some of the core would be visible when the dial isn't popped up).
 * In the flashbacks, the Rust Bucket has blue and red stripes in some scenes and brown stripes in others.
 * When Ben times out as XLR8, 16-year old Ben's time-out is heard.
 * When Big Chill and Hypnotick reached Billions Tower, Captain Nemesis's tower was not next to it.
 * After Khyber was talking to Rook when Ben figured out Khyber was keeping them busy, the Omnitrix symbol on Rook's Proto-Tool is all black.

Allusions

 * One of the Plumbers had a visor like Cyclops from X-Men.

Continuity

 * Gwen mentions several events from Ben 10 vs. the Negative 10: Part 2 while approaching Mt. Rushmore, including Upchuck's destruction of the heads on Mt. Rushmore and Ben defeating the Forever King.
 * Grandpa Max mentions Necrofriggians before Ben turns into one. However, he's interrupted before he can tell Ben and Gwen what they can do.
 * The Tachyon Cannon appears after being referenced in Ultimate Aggregor.

Trivia

 * This is the first episode in which Khyber's Dog was able to switch forms without Khyber whistling for her to do so.
 * Heatblast shouts his name in this episode, like in Ultimate Alien and Humungousaur and Big Chill in Of Predators and Prey: Part 2.
 * The logo for the "Dunk Ben 10" game at the Olde Bellwood Fair is stylized like the original series logo.
 * It's explained how Bellwood was founded, and that it was named after wooden bells.
 * In the flashback, Malware's cannon is on his left hand, while in the present, it's on his right.
 * This is because Malware is able to switch which hand he's using the gun for.
 * When 11-year old Ben asks Max what a "Magister" is, he just avoids the question.
 * This is also similar to how in Ben 10: Destroy All Aliens, Gwen asks Azmuth what mana is, who just replies "you'll find out soon enough".