The Binding of Isaac Wiki

Eternal God Eternal Challenge Room ClosedEternal Challenge Room Open

An Eternal Challenge Room is the Eternal variant of the Boss Challenge room, with the difference in that it has the health requirements of a regular challenge room. On the map, it is symbolized by an upright glowing white sword. The door has a single glowing sword over it. Inside is an Angel Room with an Angel Room pool prize. Like the Boss Rush Room, taking the prize initiates the fight. Two to three waves of Eternal variant bosses and/or monsters will spawn, with 2-3 boss enemies each wave being the most common.

This special room is very rare and only appears if Hard Mode is on. At the start of the room, the player also gets a random amount of Hearts. According to Florian Himsl himself, teleporting out of this room is not possible[1] (though using Dad's Key during waves can actually open the door and thus leave the room before finishing all waves). Every eternal boss will drop an Eternal Heart, meaning that the player will get at least one free heart container.