Underground River

Whenever you discard a creature card, you may pay 2U. If you do, create a tapped token that's a copy of that card, except it's a 4/4 black Zombie.

Whenever one or more artifact creatures you control deal combat damage to a player, you get EE (two energy counters). At the beginning of your end step, you may pay one or more E. If you do, create an X/X colorless Vehicle artifact token named Nalaar Aetherjet with flying and crew 2, where X is the amount of E paid this way.

Whenever you cast an Artificer or artifact spell, you get E (an energy counter). At the beginning of combat on your turn, you may pay EEE. When you do, create a token that's a copy of target permanent you control, except it's a 5/5 artifact creature in addition to its other types and has haste. Sacrifice it at the beginning of the next end step.

Vigilance, menace Whenever you attack, draw a card, then discard a card. Whenever you draw a card, Zombies you control get +1/+1 until end of turn.

Creatures you control that are Zombies and/or tokens get +1/+1 and have flying. Whenever one or more cards leave your graveyard, create a 1/1 white Zombie creature token.

Flying At the beginning of each end step, put X +1/+1 counters on each creature you control, where X is the number of creatures that died under your control this turn.

As this enchantment enters, choose a creature type. Creatures you control of the chosen type get +1/+0. At the beginning of your end step, for each token you control of the chosen type that entered this turn, create a token that's a copy of it.

Whenever an opponent activates an ability of a permanent that isn't a mana ability, you create a 1/1 white Zombie creature token. This ability triggers only once each turn.