When a male sticks his penis in a rectum and then proceeds to slap the male/female in the face with his penis, leaving a brown spot what looks like a poopie mushroom.

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.