Splendor Mare is a uncommon Creature — Elk Unicorn card from The List (PLST), collector number IKO-32. Current market price: $0.18, TCGplayer market prices via Scryfall.
Lifelink Cycling {1}{W} ({1}{W}, Discard this card: Draw a card.) When you cycle this card, put a lifelink counter on target creature you control.