Call from Beyond

Whenever a spirit enters the battlefield under
your control, you gain 1 life and put a ritual
counter on call from beyond. Then if there are 10
or more ritual counters on call from beyond, each opponent loses 1 life.
{4}{u}{u}, Exile call from beyond: Tap up to X
target creatures and put a stun counter on each
of them, where X is the amount of ritual counters
on call from beyond. Then if X is 10 or more,
you may take an extra turn after this one.