Rootwire Amalgam is a mythic Artifact Creature — Golem card from The Brothers' War Promos (PBRO), collector number 203s. Current market price: — (foil $1.71), TCGplayer market prices via Scryfall.
Prototype {1}{G} — 2/3 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.) {3}{G}{G}, Sacrifice this creature: Create an X/X colorless Golem artifact creature token, where X is three times this creature's power. It gains haste until end of turn. Activate only as a sorcery.