Unmanned Wall-hitting Machine “MUJIDON-KUN” Mk. I [Threat]
chair, fan, radio, folding cart, drum pedal, etc.
Based on the concept “Kabe-don,” internet slang for banging the wall, mainly used by shut-in’s as way of communicating with family member. The image is to intimidate parents or neighbors.

Unmanned Wall-hitting Machine “MUJIDON-KUN” Mk. II [Sorrow]
chair, fan, radio, folding cart, drum pedal, low-speed motor, etc.
Based on the same concept as for the Mk. I.
Sorrow version is to say that people bang the wall when they’re sad too.