Lurking Skirge

When a creature is put into an opponent's graveyard from the battlefield, if Lurking Skirge is an enchantment, Lurking Skirge becomes a 3/2 Phyrexian Imp creature with flying.

Skittering Skirge

Flying
When you cast a creature spell, sacrifice Skittering Skirge.

Carnival of Souls

Whenever a creature enters, you lose 1 life and add {B}.

Phyrexian Tower

{T}: Add {C}.
{T}, Sacrifice a creature: Add {B}{B}.

Sleeper Agent

When Sleeper Agent enters, target opponent gains control of it.
At the beginning of your upkeep, Sleeper Agent deals 2 damage to you.

Skittering Horror

When you cast a creature spell, sacrifice Skittering Horror.

Dark Ritual

Encroach

Target player reveals their hand. You choose a nonbasic land card from it. That player discards that card.

Phyrexian Negator

Trample
Whenever Phyrexian Negator is dealt damage, sacrifice that many permanents.

Darkest Hour

Planar Void

Whenever another card is put into a graveyard from anywhere, exile that card.

Flesh Reaver

Whenever Flesh Reaver deals damage to a creature or opponent, Flesh Reaver deals that much damage to you.

Vebulid

Vebulid enters with a +1/+1 counter on it.
At the beginning of your upkeep, you may put a +1/+1 counter on Vebulid.
When Vebulid attacks or blocks, destroy it at end of combat.

Attrition

{B}, Sacrifice a creature: Destroy target nonblack creature.

Swamp

Priest of Gix

When Priest of Gix enters, add {B}{B}{B}.

Sanguine Guard

First strike
{1}{B}: Regenerate Sanguine Guard.