Leyline of Mutation

Delirium — This spell costs 2 less to cast as long as there are four or more card types among cards in your graveyard. Destroy target nonland permanent.

Choose one — • Destroy all tapped creatures. • Destroy all untapped creatures.

Return target creature card from your graveyard to the battlefield with a finality counter on it. (If a creature with a finality counter on it would die, exile it instead.) Flashback 3WWB (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Vigilance Eerie — Whenever an enchantment you control enters and whenever you fully unlock a Room, put a possession counter on this creature. When this creature dies, create an X/X blue Spirit creature token with flying, where X is the number of counters on this creature.

Destroy target creature or enchantment. You lose 2 life.

Survival — At the beginning of your second main phase, if this creature is tapped, put a flying, lifelink, or +1/+1 counter on it. Whenever this creature or another creature you control dies, if it had counters on it, put those counters on up to one target creature.

As an additional cost to cast this spell, tap two untapped creatures and/or lands you control. Trample

Reach When this creature enters, surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.) 4BG, T, Sacrifice this creature: Create a number of 1/1 black and green Insect creature tokens with flying equal to the number of card types among cards in your graveyard.