Ashima, Mirror's Ire

Whenever a nontoken creature enters the
battlefield under your control, create a token
that's a copy of that creature. Sacrifice that token
at the beginning of the next end step.
{w}{u}{b}{g}: You may put a permanent card from
your hand onto the battlefield as a face-down
2/2 morph creature. For as long as that card
remains face-down, it has "{4}: Exile this card,
then return it to the battlefield face-up under
your control."