Referee Squad is a uncommon Creature — Homunculus card from March of the Machine (MOM), collector number 327. Current market price: $0.24 (foil $0.36), TCGplayer market prices via Scryfall.
Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.) Vigilance When this creature enters, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)