蹭课

蹭 = 足 + 曾 : The firefly (曾) is too lazy to fly on its own. To get to the other side of the engine's bathroom ((e)ng4) it is freeloading (蹭) by hanging on to a football (足) thrown by the King of Chu (c).

课 = 果 + 讠 : Karl Marx (k) notices an advertising column (讠) in the elevator's bathroom (e4). He decides to teach these capitalists a lesson (课) and throws grapes (果) at the ads, messing them all up. That'll teach them!