Marnin Voss

Eminence — Whenever a creature you control
becomes the target of a spell or ability an
opponent controls, if Marnin Voss is in the
command zone or on the battlefield, you may
pay X. If you do, that spell or ability's controller chooses to either have you gain X life, or counter
the spell.
{t}: Exile all creatures you control, then return
those cards to the battlefield under your
control.