Eaten Alive

As an additional cost to cast this spell, sacrifice a creature or pay {3}{B}.
Exile target creature or planeswalker.

Devouring Swarm

Flying
Sacrifice a creature: This creature gets +1/+1 until end of turn.

Go for the Throat

Fretwork Colony

This creature can't block.
At the beginning of your upkeep, put a +1/+1 counter on this creature and you lose 1 life.

Virus Beetle

When this creature enters, each opponent discards a card.

Swarm of Bloodflies

Flying
This creature enters with two +1/+1 counters on it.
Whenever another creature dies, put a +1/+1 counter on this creature.

Subtle Strike

Choose one or both —
• Target creature gets -1/-1 until end of turn.
• Put a +1/+1 counter on target creature.

Choice of Damnations

Target opponent chooses a number. You may have that player lose that much life. If you don't, that player sacrifices all but that many permanents of their choice.

Nantuko Husk

Sacrifice a creature: This creature gets +2/+2 until end of turn.

Torment of Scarabs

Enchant player
At the beginning of enchanted player's upkeep, that player loses 3 life unless they sacrifice a nonland permanent of their choice or discard a card.

Village Rites

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Mortician Beetle

Whenever a player sacrifices a creature, you may put a +1/+1 counter on this creature.

Endless Cockroaches

When this creature dies, return it to its owner's hand.

Heartstabber Mosquito

Kicker {2}{B} (You may pay an additional {2}{B} as you cast this spell.)
Flying
When this creature enters, if it was kicked, destroy target creature.

Fumulus, the Infestation

Flying, deathtouch
Whenever a player sacrifices a nontoken creature, create a 1/1 black Insect creature token with flying.
Whenever an Insect, Leech, Slug, or Worm you control attacks, defending player loses 1 life and you gain 1 life.