Monastery Mentor is a mythic Creature — Human Monk card from Fate Reforged (FRF), collector number 20. Current market price: $1.84 (foil $6.54), TCGplayer market prices via Scryfall.
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.) Whenever you cast a noncreature spell, create a 1/1 white Monk creature token with prowess.