msem-instigator

You may have Snowfield Doppelganger enter as a copy of any creature on the battlefield, except it has “While a player is choosing targets as part of casting a spell, that player must choose at least one other creature that shares a name with this creature if able.”

Look at the top five cards of your library. You may reveal a nonland card from among them. If you do, put that card into your hand and cast a copy of it without paying its mana cost. Put the rest into your graveyard.

Discard a card: Unseen Maniac gets +1/+1 and can't be blocked this turn.
Whenever Unseen Maniac deals combat damage to a player, draw a card.

Whenever an opponent casts a spell, that player mills X cards, where X is that spell's mana value.

Flash
When Wiretapper enters, choose one —
• Exile target spell. For as long as that card remains exiled, its owner may play it. A spell cast this way costs {2} more to cast.
• Create a copy of the card with target spell's name. You may cast the copy. (You still pay its costs.)

At the beginning of your end step, if you're horrific, you draw a card and you lose life equal to the number of cards in your hand. (You're horrific as long as you've sacrificed a permanent or discarded a card this turn.)

Bedfellow can't block or be blocked.
Exile two cards from your graveyard: Bedfellow gets +1/+1 until end of turn.

Target opponent sacrifices a creature.
Rerun (If you cast this from your hand, exile it as it resolves. Whenever a creature you control dies, you may cast this card from exile without paying its mana cost.)

Target player discards two cards.
Rerun (If you cast this from your hand, exile it as it resolves. Whenever a creature you control dies, you may cast this card from exile without paying its mana cost.)

Return target creature card from a graveyard to the battlefield. Then if that card wasn't put into a graveyard from the battlefield this turn, exile it.

Flying
At the beginning of your end step, put a +1/+1 counter on Lepidopteradator if you're horrific. Otherwise, sacrifice it. (You're horrific as long as you've sacrificed a permanent or discarded a card this turn.)

Living Broadcast can't block.
Whenever you cast a spell from exile, you may return Living Broadcast from your graveyard to your hand.

Sacrifice a creature or discard a card: Exile the top card of target player's library. You may cast that card for as long as it remains exiled. Any player may activate this ability but only once each turn and only during their turn.
You and permanents you control have hexproof from spells that were exiled with Mr. Jackston or that share a name with a card exiled with Mr. Jackston.

At the beginning of each player's upkeep, that player discards a card. If that player has no cards in hand, instead they sacrifice a permanent. If they control no permanents, instead they lose the game.

Destroy target creature or planeswalker. Each player loses life equal to that permanent's mana value.

At the beginning of your upkeep, each player discards a card.
Whenever Waking Watcher attacks, if defending player has no cards in hand, it gets +3/+3 and gains menace until end of turn.

At the beginning of each player's end step, if they aren't horrific, Bloody Valentine deals 2 damage to that player. (You're horrific as long as you've sacrificed a permanent or discarded a card this turn.)

Choose one. If you're horrific, you may choose both instead. (You're horrific as long as you've sacrificed a permanent or discarded a card this turn.)
• Destroy target artifact.
• Catastrophic Crash deals 3 damage to target creature.

Gain control of target creature until end of turn. Untap it. It gains haste until end of turn.
Rerun (If you cast this from your hand, exile it as it resolves. Whenever a creature you control dies, you may cast this card from exile without paying its mana cost.)

As an additional cost to cast this spell, sacrifice a creature.
Create X Treasure tokens, where X is the sacrificed creature's mana value.

Whenever a player casts a spell, put a doom counter on Foreboding Presence.
At the beginning of each player's end step, if no spells were cast this turn, sacrifice Foreboding Presence. It deals damage equal to the number of doom counters on it to that player.

Menace
At the beginning of your end step, He of All Hallow's Eve deals damage equal to its power to you unless you're horrific. (You're horrific as long as you've sacrificed a permanent or discarded a card this turn.)

Other creatures you control get +2/+0 and have menace.
Whenever another creature you control dies, if it wasn't sacrificed, sacrifice a creature.

First strike
Whenever a creature dealt damage by Roadside Reaper this turn dies, you may discard a card. If you do, put a +1/+1 counter on Roadside Reaper and draw a card.

Discard your hand. Draw cards equal to the number of creatures that died this turn.