Nirvana, Goddess of Poisons

Infect, Flying, Planeswalk (If this creature would
leave the battlefield, instead exile it
with a planar counter on it for each creature
you control.)
Whenever a creature you control dies, if this
creature is in exile, remove a planar counter
from it. Then, if this creature has no planar
counters on it, put it onto the battlefield.
She can conjure any poison out of anywhere.
Those who crossed her would tell you if they could.