Esper Sentinel is a rare Artifact Creature — Human Soldier card from Modern Horizons 2 (MH2), collector number 12. Current market price: $48.16 (foil $75.66), TCGplayer market prices via Scryfall.
Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays {X}, where X is this creature's power.