Radiant Astral Challenge is an unlockable room in Heaven's Call, a mod for The Binding of Isaac.

The Radiant Astral Challenge Room is a variant of the Astral Challenge Room.

If Double or Nothing is unlocked, stars will appear in the room the first time it is entered. Collecting all of them will make the boss battle more difficult but will also grant Isaac a Holy Card shield. When the boss is defeated, an extra item from a random pool will be rewarded.

Getting hit during the battle will prevent the extra reward from appearing and remove the item originally spawned in the room from Isaac's inventory.

Complete Tower of Babel challenge on ascended difficulty.

The Radiant Astral Challenge does not have an associated item pool.

• Download Heaven's Call from the Steam Workshop.