Arahbo, roar of the world

Emenence—at the beginning of combat on your turn, if Arahbo, is in your command zone or on
the battlefield another target cat you controll gets +3/+3 until end of turn.
Whenever another cat you controll attackes
you may pay {1}{g}{w}, if you do it gets +x/+x and trample until end of turn, where x is that creatures power.