In it's purest form, the parson's gambit involves nothing more than a surprise attack while a man is in the irreversible throes of digestive egress. In other words, harassing a man while he is taking a shit. As it is commonly known that once a bowel movement has begun, no power on earth can stop it. The victim will therefore be forced to endure any and all schemes and embarrassments imaginable.

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.