Napalm grenade

Historically, Napalm is a mixture, of chemicals which, when mixed with gasoline, makes a sticky incendiary gel. Developed by the U.S. in World War II, by a team of Harvard chemists led by Louis Fieser, its name is a combination of its original ingredients names:
 * aluminum salts of naphthenic and palmitic acids = napalm

The name has since evolved, from just the gasoline and Napalm gel, to mean any substance that causes intense fires upon ignition.

In the Halo Universe, the Firebomb Grenade was used by UNSC forces in the Halo Novels. It however, is not in Halo 3, since its idea has been replaced by the Type-3 Grenade, used primarily by Brute Stalkers.