sending an email to an unintended party; the result of which leads to a spear-like feeling to the gut for the sender, the receiver, and all the friends of both who see the email and wince in pain upon seeing such stupidity distributed.

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.