Furnace Gremlin is a uncommon Creature — Phyrexian Gremlin card from March of the Machine (MOM), collector number 139. Current market price: $0.13 (foil $0.05), TCGplayer market prices via Scryfall.
{1}{R}: This creature gets +1/+0 until end of turn. When this creature dies, incubate X, where X is its power. (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.)