Serene Sleuth is a rare Creature — Human Detective card from Murders at Karlov Manor Commander (MKC), collector number 14. Current market price: $0.20, TCGplayer market prices via Scryfall.
When this creature enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.") At the beginning of combat on your turn, investigate for each goaded creature you control. Then each creature you control is no longer goaded.