Rogwhelp, Groveling Hierophant

Rogwhelp, Groveling Hierophant cannot be sacrificed.
Whenever another creature enters the battlefield,
if its power is greater than each other creatures'
power, its controller may gain control of Rogwhelp.
{t}{w/b}: create X 0/1 Kobold creature tokens with
"this creature can't block", where X is the greatest
power amongst creatures you control.