Sailor Cosmos

Lifelink, flying, cascade {4}
When Sailor Cosmos enters the battlefield, add one
+1/+1 counter for each senshi you control. Add a
+1/+1 counter every time a creature transforms.
{x}{t}: Galaxy Cauldron - Exile {x} cards from the
top of your library. You may play one without
paying the mana cost. The rest you may play as
long as it is your turn.