Amzu, Swarm's Hunger (24) [Ravnica: Clue Edition]

Flying, menace Other Insects you control have menace. Whenever one or more cards leave your graveyard, you may create a 1/1 black and green Insect creature token, then put a number of +1/+1 counters on it equal to the greatest mana value among those cards. Do this only once each turn.