Enemies and NPCs I designed for 'Ripley The Reaper', a 3D platformer I was working on for a while.
Since Miasma is essentially a toxic puff of smoke in a robot suit, that became the main theme of the enemies - make them also toxic puffs of smoke, but in lesser mechanical suits. I really wish we got to modelling these guys before the project got cancelled.
There were also meant to be Reaper NPCs who would pick on Ripley before Miasma would invade, and would later become enemies possessed by Miasma's minions.