As an additional cost to cast this spell, sacrifice a creature.
Return a creature card from your graveyard to the battlefield, then return another creature card from your graveyard to your hand.

Chalice of the Void enters the battlefield with X charge counters on it.
Whenever a player casts a spell with converted mana cost equal to the number of charge counters on Chalice of the Void, counter that spell.

Tap up to two target creatures. Those creatures don't untap during their controller's next untap step.
Madness (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Put target creature into its owner's library second from the top.

Strive — This spell costs more to cast for each target beyond the first.
Any number of target creatures each get +2/+2 until end of turn. Untap those creatures.

Return target nonland permanent to its owner's hand. Then that player discards a card if you control a Zombie.

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for or one mana of that creature's color.)
When Conclave Tribunal enters the battlefield, exile target nonland permanent an opponent controls until Conclave Tribunal leaves the battlefield.

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for or one mana of that creature's color.)
Covenant of Blood deals 4 damage to any target and you gain 4 life.

: Cuombajj Witches deals 1 damage to any target and 1 damage to any target of an opponent's choice.

When you sacrifice a Clue, transform Daring Sleuth.

Destroy target creature. Search your library for a basic land card, put it onto the battlefield tapped, then shuffle your library.

Each opponent loses two times X life. You gain life equal to the life lost this way.

Choose up to four target cards in your graveyard. If you control a Bolas planeswalker, return those cards to your hand. Otherwise, an opponent chooses two of them. Leave the chosen cards in your graveyard and put the rest into your hand.
Exile Deliver Unto Evil.

All creatures gain fear until end of turn. (They can't be blocked except by artifact creatures and/or black creatures.)
Cycling (, Discard this card: Draw a card.)
When you cycle Dirge of Dread, you may have target creature gain fear until end of turn.

Return all nonland permanents with converted mana cost X or less to their owners' hands.

As an additional cost to cast this spell, you may reveal a Dragon card from your hand.
If you revealed a Dragon card or controlled a Dragon as you cast this spell, this spell can't be countered.
Draw four cards.

Choose target creature. Mill four cards, then that creature gets -1/-1 until end of turn for each land card in your graveyard.

Flying
, : Target attacking Vampire gets +1/+1 until end of turn.

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

Constellation — Whenever Eidolon of Blossoms or another enchantment enters the battlefield under your control, draw a card.