Alien forms used by Ben:
1) Echo Echo
3) Four Arms
Alien forms used by Gwen:
Alien forms used by Kevin:
3) Way Big
It is revealed that if Echo Echo is holding something when he duplicates himself, that object will be duplicated also.
Kevin has been keeping the yellow Techadon from "Greetings From Techadon" in his garage.
Gwen: (as Rath) Lemme tell ya somethin', unstoppable Techadon battle robot! (rips off the Techadon's head, then crushes it) You should've quit while you were still a head!
Ben: The Ultimatrix is not a weapon.
Inspector #13: Perhaps, but it soon will be.
Inspector #13: Escape is not possible, terran. Surrender is the logical choice.
Ben: Yeah, I'm more of an intuition kind of guy.
Inspector #13: I am Inspector #13, Weaponmaster of Techadon. You are implicated in my ongoing investigation of failed Techadon units.
Ben: You're a Weaponmaster. Nobody's ever even seen one of you guys.
Inspector #13: Correction. No one has ever seen us and lived.
Ben: It would be a really good idea to let me go right now! Don't you know who I am?
Inspector #13: Benjamin Kirby Tennyson. Terran. Human. Active Plumber agent. Planetary and galactic protector.
Ben: Guess you do.
Gwen: (to Kevin) I thought we had an agreement: you stop sleeping in your garage, and I stop bugging you about sleeping in your garage.
The Weaponmaster's computer classifies Nanomech as an "unidentified biomechanical organism." This fits its description of "part drone, part human" from Ben 10: Alien Swarm.