Infernal Denizen

Oracle Text

At the beginning of your upkeep, sacrifice two Swamps. If you can't, tap Infernal Denizen, and an opponent may gain control of a creature you control of their choice for as long as Infernal Denizen remains on the battlefield.

T: Gain control of target creature for as long as Infernal Denizen remains on the battlefield.

Card Rulings

10/4/2004 You must sacrifice the Swamps if you can. You can’t choose not to pay if you have them.
10/4/2004 You should always have one creature for your opponent to take (i.e. the Denizen). If by chance you have no creature for your opponent to take, then they don’t get one. Remember that taking a creature is optional so your opponent is not forced to take the Denizen.