From Destinypedia, the Destiny wiki
CHAOS DOGMA is a SIVA-altered Omolon Cocytus SR4 Scout Rifle. It can be acquired as a random drop from the Wrath of the Machine Raid after killing Aksis, Archon Prime. Unlike other traditional Omolon weapons, it does not have the trademark liquid ammo. It has multiple SIVA wires connected the port of where the liquid would be.