They made a year two version that modifed the perk so it causes a flame similar to the titan thermite grenade and it activates when yu hit something, but if you hold down the trigger continuously after firing and release it, the rocket will release a massive firebomb that lights enemies on fire and causes massive damage. I know this as I got it from a LEGENDARY HEAVY engram. PS I also got Thunderlord on the same day from an exotic engram :)