Tar'wond Greatfang

Trample, Menace.
When Tar'wond Greatfang enters the battlefield,
it deals damage equal to its power to target
creature an opponent controls.
Whenever Tar'wond Greatfang attacks, you
may pay {r}{g}. If you do, it gets +X/+0 until end
of turn,where X is the greatest power among
creatures you control.