Lineprancers is a uncommon Creature — Centaur Performer card from Unfinity (UNF), collector number 146. Current market price: $0.05 (foil $0.15), TCGplayer market prices via Scryfall.
When Lineprancers enters, you get {TK}{TK}, then you may put a power and toughness sticker on a creature you own. {3}{G}: Target creature you don't control blocks target creature you control with a power and toughness sticker on it other than Lineprancers this turn if able.