Valar, Soul Weaver

Whenever a creature enters the battlefield under your control, put a +1/+1 counter on Valar, Soul Weaver.
Other creatures you control gain +1/+1 for each +1/+1 counter on Valar, Soul Weaver.
Remove a +1/+1 counter: Prevent damage that would be dealt to Valar, Soul Weaver this turn.