Cnidarian's Tiny Nebula

A miniature nebula bursts out of your body. The stars of the nebula float up to 15 feet from you, and shed dim light for 15 feet beyond that. The nebula takes the shape of your patron, or your patron's home, or a cosmic body of your choosing. The area of the nebula is lightly obscured. Creatures that start their turn in this space or creatures who enter this space for the first time must make a Dexterity saving throw.

On a failed save, the creature takes 3d8 Radiant damage, colliding the stars of the nebula, and are outlined with a galactic aura for 1 minute. Creatures affected by this aura shed dim light in a 10 foot radius. Any attack roll against an affected creature has advantage, and the affected creature cannot benefit from being invisible.

On a successful save, the creature takes half damage, and is not outlined in the galactic aura.