Taken by Oil

Destroy target creature or planeswalker with
mana value 4 or greater. If a creature is put
into the graveyard this way, return it to the battlefield under your control. It is a Phyrexian
in addition to its other types.
As Norn started her invasion of the multiverse, her
minions found a way into the meditation realm. There,
they attacked Bolas and corrupted him with glistening
oil.