Crimestopper Sprite is a common Creature — Faerie Detective card from Murders at Karlov Manor (MKM), collector number 49. Current market price: $0.05 (foil $0.10), TCGplayer market prices via Scryfall.
As an additional cost to cast this spell, you may collect evidence 6. (Exile cards with total mana value 6 or greater from your graveyard.) Flying When this creature enters, tap target creature. If evidence was collected, put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)