Nozdormu

Flying, first strike
When Nozdormu enters the battlefield, untap
all your permanents and you gain an extra turn
after this one.
At last it has come to pass. The moment of my demise.
The loop is closed. My future self will cause no more
harm. Still, in time, I will... fall to madness. And
you, heroes... will vanquish me. The cycle will repeat.
So it goes.