Chakota

The Chakota is a six-foot-tall worm-like mass of sickly purple-veined muscle covered in dozens of human faces that weep, shout, and cry out with great woeful feeling.

In the RPG...

I was torn on whether to include the Chakota on my list. Like the Animiculi, which I did exclude, it feels more like a unique entity tied to a campaign—in this case, Masks of Nyarlathotep—than a monster which could be re-purposed elsewhere. The only reason I'm leaving it in, is that it could technically be relocated and used in a different setting, despite my preconceptions.

    When the Chakota attacks, it uses up to 8 of its faces to bite the victim, latching on. It is immune to physical weapons, though fire, magic, and electricity can hurt it. It can also be suffocated or drowned if the mouths are covered. The biggest danger of the Chakota is the Sanity loss. Seeing it can take up to 20 Sanity points—which is doubled or tripled if the Investigator knows one of the faces—as well as up to 10 points for being bitten. On the upside, however, is the fact that it's typically kept captive in a well, so an Investigator would need to be thrown (or fall) into said well to become its victim.

In a video game...

Due to the Chakota's typical lack of mobility, I think it would only work as a plot device, where the player would be captured and intentionally sacrificed to the creature. I can move, but with 4 MOV, would be easily outrun. On a related note, I think Masks of Nyarlathotep would make for an awesome video game adaptation.

In a film...

The body-horror inherent in the Chakota's appearance would make for a horrific movie monster, combined with its wailing and screams. As with the above, straight-up adapting Masks of Nyarlathotep would probably be the best option.