Eldritch Retort (3.5e Invocation)

When you use your eldritch blast, it instead forms an orb of glowing energy which orbits you. If you are attacked by a creature within the range of your eldritch blast, the orb automatically fires your eldritch blast as a non-action. You can have only one eldritch retort at a time, plus an additional casting at 5th level and every five levels beyond (maximum five at 20th). No matter how many eldritch retorts you have floating around you, only one eldritch retort is fired per attack against you.

Eldritch retort lasts for 24 hours or until expended.