Niv-Mizzet's Final Stand

Whenever a creature you control dies, draw a
card.
Whenever you draw a card, you may sacrifice
Niv-Mizzet's Last Stand. If you do, search your library for a legendary dragon creature card and
put it into your hand. Then shuffle your library.
Niv-Mizzet stood before Nicol Bolas, ready to enact
the most insane plan he had ever created.