Maester Seymour is a rare Legendary Creature — Human Elf Cleric card from Final Fantasy Commander (FIC), collector number 160. Current market price: $1.02 (foil $6.74), TCGplayer market prices via Scryfall.
At the beginning of combat on your turn, put a number of +1/+1 counters equal to Maester Seymour's power on another target creature you control. {3}{G}{G}: Monstrosity X, where X is the number of counters among creatures you control. (If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.)