Elvish Vatkeeper is a uncommon Creature — Phyrexian Elf card from March of the Machine (MOM), collector number 223. Current market price: $0.21 (foil $0.18), TCGplayer market prices via Scryfall.
When this creature enters, incubate 2. (Create an Incubator token with two +1/+1 counters on it and "{2}: Transform this token." It transforms into a 0/0 Phyrexian artifact creature.) {5}: Transform target Incubator token you control. Double the number of +1/+1 counters on it.