I downloaded a zip file of Vinesauce's mapping contest from 2019 and was sorting through the various wads to see what I wanted and deleted stuff that I didn't. I stumbled across a wad called: "Agonizing dreams" by dkroode. Towards the end of the map, you get a red super shotgun that fires several rockets in a spread that's pretty powerful. I'm wondering where I can find this gun in a weapon mod, or possibly the mod that it goes to? I tried googling "Rocket-launching shotgun" but just found explanations about Doom's normal weapons. Any ideas?
dkroode_-_Agonizing_Dreams.rar