Lulu

Soulbond (You may pair this creature with another unpaired creature when either enters the battlefield.
They remain paired for as long as you control both of
them.)
As long as I am paired with another creature,
both creatures are 4/4.
Limit Break (Transform me when conditions are met.
I keep all counters when flipped.)4 or more
creatures are paired with other creatures at the
end of turn.