Pusheen, Destroyer of worlds

Pusheen,Destroyer of worlds enters the battlefield
with {x}/{x}, where {x} is the number of friends
you have.
When Pusheen, Destroyer of worlds enter the battlefield you may sacrifice yourself (the player)
to win the game, this ability can only be used
once, and your opponent may choose to sacrifice themselves
in the name of Pusheen, destroyer of worlds
to win the game instead.