Laringus, the Mongrel

Whenever Laringus, the Mongrel is blocked by
or blocks a Human, it gets +2/+0 until end of
turn.
Whenever a Human enters the battlefield under
the control of an opponent and Laringus is in
your graveyard, you may pay {4}{b}{b}. If you do,
return Laringus to the battlefield tapped under
your control. Exile it the next time it would die.