Infernal DenizenHow it works & interactions with other cards

A Price in Peat

The most important thing to remember about Infernal Denizen is its mandatory upkeep cost. At the beginning of your upkeep, you must sacrifice two Swamps if you control them; you cannot voluntarily choose to fail the payment to trigger the second part of the ability. If you have the Swamps, they must go to the graveyard. If you control only one Swamp or none at all, the penalty occurs: the Denizen is tapped, and an opponent may choose to take one of your creatures for as long as the Denizen stays on the battlefield.

The Step-by-Step Betrayal

When your upkeep begins, the ability goes on the stack. First, the game checks if you can sacrifice two Swamps. If you can, you do so, and the ability resolves. If you cannot, you tap the Denizen. Then, an opponent of your choice may choose a creature you control. This is optional for them, but if they choose a creature, they gain control of it immediately. This control effect lasts as long as Infernal Denizen remains on the battlefield; if the Denizen leaves, the creature returns to its previous owner.

Mastering the Tap Ability

Beyond its upkeep cost, Infernal Denizen has a powerful activated ability. By tapping it, you gain control of any target creature. Like the penalty effect, this control lasts only as long as Infernal Denizen remains on the battlefield. If you lose control of the Denizen or it is destroyed, the creature you stole will immediately return to your opponent. Because the Denizen taps itself to activate this, and also taps itself if you fail the upkeep, timing your mana and untap effects is crucial.

Strategic Considerations

Since the Denizen's penalty allows an opponent to take any creature you control, this includes the Denizen itself. If you have no other creatures, your opponent can choose to take the Denizen, effectively using your own card against you. To mitigate this, ensure you have a surplus of Swamps or ways to remove the Denizen in response to its own trigger if you cannot pay the cost.

Interaction examples

Managing the Upkeep with Sheoldred

Sheoldred, Whispering One

If you control both creatures during your upkeep, both 'At the beginning of your upkeep' triggers happen. You can choose to resolve Sheoldred's trigger first to return a creature card from your graveyard to the battlefield. Afterwards, when Infernal Denizen's trigger resolves, if you don't have two Swamps, your opponent could choose to take your newly returned creature or Sheoldred herself!

Stealing and Sacrificing

Meteor Golem

You can use Infernal Denizen to tap and take control of an opponent's Meteor Golem. If you then fail your next upkeep cost because you lack Swamps, and your opponent chooses to take the Meteor Golem back, the Golem's 'enters the battlefield' ability will not trigger again, as it never actually left the battlefield; it only changed controllers.