Despite the word twat twat the definition merely means stupid fraud or stupid liar. It is somewhat analogous to troll troll but indicates the person, besides being of substandard intelligence, is a fraud (having a false identity or possibly paid to spread disinformation) or just spreads falsehoods. The word was first used on Twitter about 2019.

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.