Matzalantli, the Great Door // The Core

T: Draw a card, then discard a card.

4, T: Transform Matzalantli. Activate only if there are four or more permanent types among cards in your graveyard. (Artifact, battle, creature, enchantment, land, and planeswalker are permanent types.)

(Transforms from Matzalantli.)

Fathomless descent — T: Add X mana of any one color, where X is the number of permanent cards in your graveyard.