While their function in Doom 64 is unchanged to that of the classic Mancubus, their appearance is greatly altered. Their pupil-less eyes have blue sclera instead of green, their bodies have less fat and a more bear-like face, are taller and wear a metal body harness. Their fireballs are smaller and appear more like fiery brimstone. Their movement style (body bobbing continually to the sides while walking, with both arms rigidly outstretched in front of its body) is very reminiscent of zombies in real-life vintage undead-themed horror movies.
This type of Mancubus appears on the cover of an issue of Nintendo Power featuring a spread of Doom 64, including a two-page poster that features it in conjunction with other demons.