msem-instigator

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
[+1]: Create a 2/2 blue Elemental Illusion creature token with flying and “Whenever this becomes the target of a spell, sacrifice it.”
[–2]: Return up to one other target nonland permanent to its owner's hand. Draw a card.

Flying
Whenever one or more creatures you control deal combat damage to a player, exile the top card of that player's library. Until end of turn, you may play cards exiled with Zorganis, Dread Specter and you may spend mana as though it were mana of any type to cast those spells.

[+1]: Each opponent discards a card. If a land card is discarded this way, create a 1/1 colorless Spirit creature token with flying.
[–2]: Until end of turn, creatures you control get +1/+1 and creatures your opponents control get -1/-1.
[–6]: Each opponent chooses up to one permanent they control of each permanent type, then sacrifices the rest.

Zygos, Underworld Scourge's power and toughness are each equal to the number of cards you own in exile and in your graveyard.
Spells you cast have “As an additional cost to cast this spell, you may exile any number of cards from your graveyard. This spell costs {1} less to cast for each card exiled this way.”