It's called "Glowing One", as basically I've implemented this challenge where if you drink a certain amount of Sierra Madre Martinis with Dean Domino in the party, he'll absorb so much radiation that his ghoulification advances (basically like what was supposed to happen to Lenny in Fallout 2). Whenever Dean's nearby you'll take radiation damage like any other Glowing One, but it means your energy weapons stay charged, and they use half the amount of ammo that they normally would. (Sounds like a bad idea to keep him nearby, except that prolonged exposure to Dean's radiation completes the
second challenge, which gets you the Rad Regeneration perk, like The Wasteland Survival Guide in Fallout 3. So effectively you get half ammo use on all energy weapons, and regenerating limbs!)
(I'll be using the glow from the Rad Regeneration perk icon in the New Vegas files to make Dean's icon glow, but I can do that much myself).