When your girl friend/boyfriend is taking a shower and you sneak up on them jump in the shower cover them with the black bag and beat the shit out of them and when their on the floor you jizz/shit/pee on them and then yell surprise.

A phrase to describe someone who is cognitively degenerating. Synonym of "going off the deep end". Can have varying degrees of severity.

Reference to the song "Hey You" by Pink Floyd. The line "and the worms ate into his brain" makes no sense in an otherwise linear and literal narration throughout the lyrics.