Even putting aside how unsettling this is… what’s the joke, and why are Buni, the headless chicken and the freakish Drumstick Babies laughing?

Bananas give off ethylene, which makes other fruit ripen more quickly, which is kind of analogous to zombies turning other people into zombies.

Except that only ripening bananas give off ethylene, but that’s all I got…

He’s freaked out because there’s a Band-Aid in the water? Am I missing something?