Nergal, Calamity Bringer

Deathtouch, ward—Discard a card.
Whenever another nondragon creature dies, return
it to the battlefield tapped and under your control.
It becomes a blue Morph with base power and
toughness 1/1 and loses all other card types.
Sacrifice 5 Morphs: Search your library for a dragon creature card and put it onto the battlefield.
Activate only as a sorcery.