Raaz, Impish Trickster

Flying
Fickle Fortune: At the beginning of each player's upkeep, that player flips a coin. If heads, they draw a card. If tails, you may draw a card.
Whimsical Revelry: Whenever a creature enters the battlefield under an opponent's control, that player may discard a card. If they don't, Raaz, Impish Trickster gains a +1/+1 counter.