Serra's Realm, Capsulized

If a planeswalker entering the battlefield causes a triggered ability of another permanent to trigger,
that ability triggers an additional time.
Whenever a planeswalker enters the battlefield,
it's controller gains three life and put a soul
counter on Serra's Realm, Capulized.
When Serra's Realm, Capulized has 7 or more
soul counters on it, you may sacrifice it. If you do,
you gain 10 life and draw a card.