Aetherplasm is a uncommon Creature — Illusion card from Guildpact (GPT), collector number 22. Current market price: $0.20 (foil $2.05), TCGplayer market prices via Scryfall.
Whenever this creature blocks a creature, you may return this creature to its owner's hand. If you do, you may put a creature card from your hand onto the battlefield blocking that creature.