Halaster Imitator

Madness {r} (If you discard this card, discard it into
exile. When you do, cast it for its madness cost or put
it into your graveyard.)
You may have Halaster Imitator enter the battlefield as a copy of any creature on the battlefield. If its madness cost was paid, it gains
haste and "sacrifice this creature at the
beginning of the next end step".
"All wizards use swords. Stop asking."