Wandertale Mentor is a uncommon Creature — Raccoon Bard card from Bloomburrow (BLB), collector number 240. Current market price: $0.24 (foil $0.29), TCGplayer market prices via Scryfall.
Whenever you expend 4, put a +1/+1 counter on this creature. (You expend 4 as you spend your fourth total mana to cast spells during a turn.) {T}: Add {R} or {G}.