Twonkies are small, furry, and generally harmless critters from the comet Twonkus-3. Twonkies are only dangerous when exposed to sound of the same “color” as themselves. Then they change into something quite horrible; Stompers, Gromps and Monstros, respectively. They are possibly related to Fibs. To make matters worse, Twonkies can also evolve into three different sub-species of Elemental Twonkies - Lightning, Ice, and Dark Matter Twonkies.
Carl took one home, it evolved into a Stomper, and Jimmy Neutron had to stop the menace.
- Twonkies are parodies of the Mogwais and Gremlins from the 1984 movie "Gremlins" and its 1990 sequel. Just as the Twonkies change into monsters, once the Mogwais eat after midnight, and they turn into Gremlins.
- Their vocal effects are done by Frank Welker, who also did the vocal effects for Jimmy's dog Goddard, as well as the voice of "Stripe" from Gremlins (1984).