Meralis, Enslaver of All

Flying,
Meralis, Enslaver of All gets +1/+1 for each
creature you control, that you don't own.
When Meralis deals combat damage to an
opponent you may pay {b}{1} and sacrifice a
creature, if you do deal damage equal to that creatures power to that opponent.
{u}{b}{r}; gain control of target creature until
end of turn.