msem-instigator

Deathtouch
When Bitterheart Bokor leaves the battlefield, you may search your library for a Curse card, reveal it, put it into your hand, then shuffle.

When Black Cat dies, target opponent discards a card at random.

Lifelink
When Black Curtain Enforcer enters, you may return target creature card with mana value 3 or less from your graveyard to your hand.

Deathtouch
{B}, Pay 1 life: Add one mana of any color. Activate this ability only once each turn.

You lose 1 life and exile the top card of your library. You may repeat this process any number of times. Then put up to two cards exiled this way into your hand.
Coalesce {5}{B}{B} (You may cast this from your graveyard for {5}{B}{B}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
Black Hole Musings's power is equal to the number of cards in exile.

Look at the top four cards of your library. Put any number of them into your graveyard and the rest on top of your library in any order.
You draw two cards and you lose 2 life.

Whenever Blackfeather Cleric enters or attacks, exile target card from a graveyard. Put a +1/+1 counter on Blackfeather Cleric if it was a permanent card. Otherwise, you gain 1 life.
Surpass {5}{B} ({5}{B}: Transform this creature. This costs {1} less to activate for each counter on it. Activate only as a sorcery.)

Flying, lifelink
Whenever Blackhearted Sphinx attacks, you may pay 3 life. If you do, draw a card.

Menace
When Blackmoat Bully dies, put a +1/+1 counter and a menace counter on target creature you control.

At the beginning of combat on each of your turns, look at the top card of your library. You may put that card into your graveyard.
Whenever a land card is put into your graveyard from anywhere, each opponent loses 1 life and you gain 1 life.

When Blacksite Moderator enters, you may pay 2 life or sacrifice a permanent. If you do, draw a card.

Lifelink
{T}, Pay 4 life or sacrifice another permanent: Draw a card.

When Blade of Reolem dies, target opponent discards a card at random.

Poisonous 1 (Whenever this creature deals combat damage to a player, that player gets a poison counter.)
Blade of the Serpent gets +1/+1 as long as an opponent is poisoned.

This spell costs {3} more to cast if it targets a card in an opponent's graveyard.
Choose target creature or planeswalker card in a graveyard that was put there from the battlefield this turn. Put that card onto the battlefield under your control.

Flying
When Bleak Condor enters, mill four cards.

When Bleeding-Edge Garroter dies, if it was in a pack, you draw a card and you lose 1 life. (Two or more creatures you control with equal power are in a pack.)

When Blightbringer enters, creatures your opponents control get -1/-1 until end of turn.
Unearth {3}{B} ({3}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the end step or if it would leave the battlefield. Unearth only as a sorcery.)

{1}{B}: Blightcaller Shaman gains deathtouch until end of turn.

Haste
When Blighted Dullahan dies, you draw a card and you lose 1 life.

{1}{B}, {T}: Target creature gets +2/+2 and gains winnow until end of turn. (Damage dealt to it also causes its controller to lose that much life.)
{3}{B}{B}, {T}: Target creature gets -2/-2 and gains winnow until end of turn.

Whenever one or more creatures attack you, you may put a -1/-1 counter on target creature.

Blighted Unicorn can't block.
Ride {3}{B} ({3}{B}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

When Blighting Ooze enters, put a -1/-1 counter on each of up to X target creatures.
As long as Blighting Ooze is on the battlefield, it has all activated abilities of each creature with a -1/-1 counter on it.

Breach (Whenever this deals combat damage to a player, you may have it become an Aura Curse until your next turn. Attach it to that player.)
At the beginning of your end step, each cursed opponent loses 2 life unless they discard a card.