Malefactor

Malefactor is the fifteenth episode of Ben 10: Omniverse.

Plot
Ben and Rook are attacked by Khyber and his dog in a festival (Olde Bellwood Days). While fighting Ben, Khyber's Dog turned into a Psycholeopterran named Hypnotick, a rare and almost extinct predator of the Necrofriggians.

Then in flashback, 11 year old Ben and Gwen along with Grandpa Max visit Mt. Rushmore for a surprise. There, Max shows them an injured Psycholeopterran saved by Plumbers from smugglers. Suddenly plumber base alarm goes off and Ben, Gwen and Max goes to solve the problem. Malware attacks the Plumber base. Ben turns into XLR8 and keeps Malware busy but the Omnitrix times out and Ben is about to be killed by Malware. Then, Max attacks him with a Tachyon Cannon which disrupts Malware but Malware regenerates and absorbs the Tachyon cannon and mutates 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 gets the Psycholeopterran DNA. Malware then tells Ben that he already got what he came for and leaves. Max realises 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 realises that Khyber and his dog are just wasting his time. Meanwhile, Rook is taking on Khyber. While talking to him, Rook realises that they have come for the Proto-TRUK. Ben reaches the Truck and is freaked out seeing Malware. Ben decides to finish Malware and turns into Humungousaur, but Malware sends a gas tanker 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 his 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
 * Madison (cameo)
 * Mr. Baumann (Ben's dream)
 * Pakmar (Ben's dream)

Past Characters

 * Ben Tennyson
 * Gwen Tennyson
 * Max Tennyson
 * Earth Plumbers
 * Plumber Jerry
 * Molly Gunther
 * Smuggled Psycholeopterran

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 Khyber's Dog

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

Errors

 * 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 Big Chill and Hypnotick reached Billions Tower, Captain Nemesis's tower was not next to it.

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.
 * Grandpa Max also 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 it 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. Most likely to keep the series continuity, as Ben and Gwen learn later in the episode Darkstar Rising.
 * 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".