Acrithas, Harbinger of Endings

Deathtouch
When Acrithas enters the battlefield, all other creatures are destroyed and a Five turn timer
begins. If Acrithas, Harbinger of Endings is
still on the battlefield in any capacity at the end
of the Fifth turn of the timer, the owner of the
card wins the game. Only one instance of the
timer may be activated at a time during the game.
"I am the end and the beginning..." Acrithas