Atraxa, Emrakul's Tool

Flying Vigilance Deathtouch Lifelink Hexproof
When Atraxa, Emrakul's Tool attacks,
Search your library for a legendary creature card
and put it onto the battlefield tapped
and attacking with
"When this creature dies, exile it."
When Atraxa, Emrakul's Tool dies,
Take and extra turn after this one