Brood Nest

When Brood Nest enters the battlefield create a
0/1 green Ripper Swarm creature token.
{1}{p/g}, {t}, Sacrifice a creature: Search your library
for a creature card with mana value equal to 1
plus the sacrificed creature's mana value, put
that card onto the battlefield, then shuffle your library. Activate this ability only any time you
could cast a sorcery.