Chrome Host Seedshark is a rare Creature — Phyrexian Shark card from March of the Machine (MOM), collector number 350. Current market price: $0.73 (foil $0.78), TCGplayer market prices via Scryfall.
Flying Whenever you cast a noncreature spell, incubate X, where X is that spell's mana value. (Create an Incubator token with X +1/+1 counters on it and "{2}: Transform this token." It transforms into a 0/0 Phyrexian artifact creature.)