Ultnil, Apex of Disaster

Trample

At the beginning of combat on your turn, all players
may reveal the top card of their library. If they do,
the player whose card has the highest converted
mana cost may goad Ultnil, Apex of Disaster until
end of turn. Then, each other player that revealed a
card may put a +1/+1 counter on Ultnil, Apex of Disaster to goad it until end of turn.

Its roar is only meant for ephemera