The Godzilla Grand-Slam Bunny-Eradicator 4000 (BE4000) is a plot device invented by KT of the writing team JAKT. It is a flamethrower designed to kill plot bunnies, as nothing kills a plot bunny better then flames. It is powered by grapeseeds.
The device made its first appearance in the story Open Season in which it was used by KT to kill plot bunnies.
It made its second appearance in Plot Bunnies return, in which it is modified to multiply plot bunnies instead of kill them. In this form it uses a beam instead of a flame. While not quite as powerful as flames, it does look cooler, which is what matters in the end, really.