Aliens (Fire in the Sky)

A group of unnamed aliens act as the central antagonists of the 1993 sci-fi horror film, Fire in the Sky. While they are the main villains of the entire film they are actually told in flashbacks as the film focuses on the experiences of an alien abduction, nevertheless the aliens serve a pivotal role and are often seen as one of the more terrifying examples of aliens and the related abduction phenomena in cinema.

History
The aliens are part of an unnamed species that appear to be engaged in a long-running scheme of brutal experimentation on humans and possibly other species, while their appearance in the film is brief they nevertheless show themselves as a tangible threat and the protagonist must brave a torturous ordeal as one of their experiments, only narrowly escaping their clutches and returning to Earth in order to share his experience with others.

It is shown that other people were not so lucky and unlike most depictions of alien abductions the aliens in this film were capable of outright murder as they were shown to have tables of mutilated human corpses, dissecting said corpses - judging by the brutal methods of experimentation and the aliens lack of care for those they abducted the practice of killing their victims was likely very common, unlike many other abduction-based species (who tend to abduct victims and then free them).

Appearance
The aliens in the film are depicted as hairless humanoids with features similar to those of the Grey - however they have a more human-like flesh tone as well as more human-sized eyes, though they are pure black, their faces lack ears or noses but do have a human-like mouth.

The film shows that these creatures have access to space-suits that closesly resemble Greys, this suggests that the alien beings in the film are indeed Greys and the traditional appearance humans attribute to Greys are actually due to seeing these aliens inside one of their space-suits.

Abilities
while any physical, psychic or supernatural powers within the aliens are not explored one extreme feature that is explored is their terrifyingly advanced technology, which allowed them to travel across space-time and abduct humans with ease : their technology is shown to be more bio-mechanical than most species, with vicious-looking machines merging with cocoon-like webbing and sticky fluids, all designed to capture and experiment on other life-forms.

the aliens are not able to survive in space, it seems, since they have a large room filled with specially designed space-suits which strongly resemble what humans have come to associate with the classic "Grey" design of large eyes and silvery "skin".