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Tear Jerker: Megas XLR
Despite the comedic tone of the series, the season two finale when Coop nearly gets himself killed.
Jamie: Coop, you're red-lining! Eject!
Coop: No!! I ain't leavin' Megas!
Also when MEGAS blew up.
In one episode, the Glorrft attempt to kill Kiva by killing her ancestor. At the end of the episode, Kiva admits to her ancestor that she is lonely in the Bad Future as she has no family that cares for her. She asks her ancestor if they want to get to know each other. Unfortunately, the ancestor was like Kiva was when the series started. She wants nothing to do with her or Coop's chaos, leaving Kiva without a family again. The look of sadness on her face sells it.