Seedglaive Mentor is a uncommon Creature — Mouse Soldier card from Bloomburrow (BLB), collector number 231. Current market price: $0.22 (foil $0.28), TCGplayer market prices via Scryfall.
Vigilance, haste Valiant — Whenever this creature becomes the target of a spell or ability you control for the first time each turn, put a +1/+1 counter on it.