Spectral Hunters

Spectral Hunters are rubbery-skinned humanoids with shark-like mouths and crab-like claws. They are typically guardians of a location or object, and can become invisible at will.

In the RPG...

The 7e Malleus Monstrorum says that Spectral Hunters are invisible, but can become visible at will, whereas the old edition says the other way around. This seems like an odd change to me. Why would an invisible creature choose to become visible? Either way, apparently certainly light or lenses can allow them to be seen. The Hunter itself is immune to all attacks. However, if the magical artifact to which they are tied is damaged, they suffer damage as well, and if it is destroyed, so are they... for a time.

    Most of the Hunter's stats have changed in the 7e Malleus Monstrorum, with only CON and INT remaining untouched. All averages have stayed the same, though the ranges have increased for STR and SIZ, and decreased for DEX and POW.

In a video game...

Spectral Hunters look cool, are reasonable foes, and their invisibility would add a nice bit of challenge, so would probably work in a video game. Their weakness would also add some interest to battling them... assuming the player figured it out.

In a film...

I have no knowledge of the Spectral Hunters' source material, though at face value, they seem like they would make an interesting and visually scary movie monster.