Monastery Mentor is a mythic Creature — Human Monk card from March of the Machine (MOM), collector number 347. Current market price: $2.34 (foil $2.47), 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.