Lawyer

A courtroom fixture who turns up whenever Big Mouth needs someone to deliver dry legal exposition with a straight face. He is brisk, procedural, and utterly unbothered by the chaos of hormone monsters and teenage panic swirling around him, treating absurd cases with the flat seriousness of a man who has seen worse.

The joke is entirely in the mismatch: a show built on shrieking id and bodily horror hands its most ridiculous moments to a calm, besuited professional. Fred Armisen's clipped, deadpan delivery makes the character's total lack of surprise the punchline, a small dose of bureaucratic normalcy dropped into total absurdity.