A person who, knowing that there friend/ significant other will insist on paying, reaches for their wallet as if to pay. But in reality, they're broke as hell.

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.