Nemean, Cattess of Peace

Cats have indestructable. Nemean gets +1/+1 for each Cat on the battlefield.
{x}{w}{r}{g}, {t}: Nemean deals X damage to any number of target creatures or players and deals X damage to you.
At the beginning of each end step, if you or a planeswalker you control took 5 or more damage this turn, exile Nemean, then return it to the battlefield transformed under its owner's control and exile all nonland permanents that aren't white or green.