Incendiary gel
From Halopedia, the Halo wiki
Template:Ratings Incendiary gel was a Covenant ammo type utilized mainly by Jiralhanae[1] and Mgalekgolo.[2]
Incendiary gel is used in Type-3 Antipersonnel/Antimatériel Incendiary Grenades, and in the Assault Cannons of Mgalekgolo, where it can be fired in mortar-like green projectiles or in a searing stream of fire.[3]
Incendiary gel burns at approximately twenty-two hundred degrees, celsius.[4], and won't burn underwater.[5] It is possibly radioactive.