Gravity Well

Tap up to two creatures your opponents control and put a stun counter on them. When you refocus
Gravity Well, instead tap X creatures and put a
Stun counter on them.

Refocus {x}{u}{u}, X Mind (When this spell
resolves, exile it. You may cast this spell from
exile for its Refocus costs. If you do, tap creatures
with Mind counters on them and remove the
required number of counters from them.)