Kiga, Endless Wrath

If Kiga was cast from your hand, he enters the battlefield with two +1/+1 counters on him.
Persist, trample
At the beginning of your upkeep, you may sacrifice another creature. If you do, put +1/+1 counters on Kiga equal to that creature's toughness. If you don't, Kiga must attack this turn if able unless you exile a creature from your graveyard.