Yawgmoth, Lord of the Wastes

Yawgmoth, Lord of the Wastes' power and
toughness is equal to the number of artifacts
under your control.
All permanents under your control are artifacts
in addition to their other types.
Whenever a creature you don't control dies,
return it to the battlefield under your control.
When Yawgmoth, Lord of the Wastes dies or is
put into exile from the battlefield, you may put
it into its owner’s library third from the top.