Guren, Conjurer of Crystals

Crystal Prison Jutsu - When Guren, Conjurer of
Crystals enters the battlefield or attacks, exile up
to one target creature until Guren, Conjurer of
Crystals leaves the battlefield.
{4}{u/r}{r/w}, {t}: Create an X/ X blue, red, and white
Dragon creature token with flying where X is
equal to the total converted mana cost of all
creature cards exiled with Guren, Conjurer of
Crystals.