well I mean promethean weapons which are light based, their version of the rocket launcher shot red light which exploded like the plasma launcher does, it was a nice weapon.
But thanks for reminding me about the sticky gun, that was an ok weapon, bit cheesy.
The Incinerattion Cannon is still in the game. It's changed to a two style shot weapon with a single pull and charge projectiles.
INCINERATION CANNON
Heavy cannon that fires a powerful energy charge. Main charge spawns submunitions on impact.
RIVER OF LIGHT
The war against the Flood led to many technical advances. All proved fruitless. Improved Incineration Cannon that will unleash a long burst of energy blasts if allowed to charge up by holding the firing trigger.
HEARTSEEKER
Forerunner Warrior-Servants were relentless on the hunt. Advanced Incineration Cannon that fires tracking energy charges.