Grayvan the Lost

When Grayvan the Lost enters the battlefield, sacrifice it unless you exile a creature card from
a graveyard. If you do, Grayvan the Lost enters
the battlefield as a copy of that creature, except it
has menace, changeling, and "{2}{u}{b}: Exile this creature, then return it to the battlefield".
"No... this is not my face... must find it... must
find my face."