The cover more than carries this one.

Not that the interior art is terrible, but it's a Brian Bolland cover, so c'mon. From 1986, The Outsiders #18, "The Firefly's Blaze of Glory" Written and edited by Mike W. Barr, art by Jerome Moore and Al Vey and Jan Duursema.

As the Outsiders practice and have a few laughs in their off-brand Danger Room (they aren't the only DC characters to have swiped one!) in L.A. a prison transport is loading, and the guards and other prisoners are also having a laugh, at the expense of one Garfield Lynns, a.k.a. Fruitfly. Er, Firefly. Although soundly mocked by all, he is able to escape from the transport with an "equalizer beam" that blended the gray of his uniform with that of the truck. At a newspaper, Firefly tries to get a classified ad to threaten the Outsiders, and is about to get bounced by security, once they stop laughing at his costume. Still, FF--that's actually on his costume, his chest logo is FF--zaps them with an illusion ray, and makes a pretty effective escape by blinding drivers with red lights.

The Outsiders aren't taking Firefly very seriously, but do want to make sure no one gets hurt. Katana deduces the clue he was trying to place in his ad, that FF was going to attack Dodger System on "Light Night," a flashlight giveaway. (Which sounds like a good way to get batteries thrown at ballplayers, but what do I know?) When Firefly sucks all the power out of the stadium, the Outsiders take him down easily, but he manages to suck the light out of Halo, including her powers! Firefly turns the tables, then escapes again; but Halo is weakened and near death.

As the rest of the team falls into a obvious trap trying to find Firefly, FF hits the Outsiders' headquarters, planning to finish Halo off and keep her powers. Still, when tricked into trying to use all Halo's powers at once, Firefly loses them: that was how Halo transformed into her civilian identity Gaby. A very protective Katana threatens to kill Firefly if Halo dies, but she recovers. Firefly gloats that he might've got beat, but he had his moment in the sun, and they can't take that away from him. Unless a telepath like Looker wipes his mind, which she does, which seems a little harsh.

We don't see this version of Firefly much after this: eventually, the Batman: the Animated Series version of a pyromaniac with a flamethrower gun and maybe jetpack wings would become the standard. Probably just as well: the light-controlling version seems interchangeable with the first Doctor Light. Both had science that should've changed the world, but instead used it to be punched in the face repeatedly by super-heroes, and both were mindwiped to forget a victory...uh-oh.