Demon's Grasp

Target creature gets -5/-5 until end of turn.

Bone Splinters

As an additional cost to cast this spell, sacrifice a creature.
Destroy target creature.

Tar Snare

Target creature gets -3/-2 until end of turn.

Walking Corpse

Nightmare

Flying (This creature can't be blocked except by creatures with flying or reach.)
Nightmare's power and toughness are each equal to the number of Swamps you control.

Vampire Envoy

Flying
Whenever this creature becomes tapped, you gain 1 life.

Swamp

Untamed Hunger

Enchant creature
Enchanted creature gets +2/+1 and has menace. (It can't be blocked except by two or more creatures.)

Dead Weight

Enchant creature
Enchanted creature gets -2/-2.

Mind Rot

Sengir Vampire

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever a creature dealt damage by this creature this turn dies, put a +1/+1 counter on this creature.

Hagra Sharpshooter

{4}{B}: Target creature gets -1/-1 until end of turn.

Rottenheart Ghoul

When this creature dies, target player discards a card.

Zulaport Cutthroat

Whenever this creature or another creature you control dies, each opponent loses 1 life and you gain 1 life.

Dutiful Return

Return up to two target creature cards from your graveyard to your hand.

Vampire Noble

Blighted Fen

{T}: Add {C}.
{4}{B}, {T}, Sacrifice this land: Target opponent sacrifices a creature of their choice.