When Riddick (Vin Diesel) and the other passengers aboard the Hunter Gratzner crash land on the planet designated M6-117 in the movie ‘Pitch Black’ (2000), they are unaware what the planet’s approaching total eclipse will unleash.
M6-117 is a mostly a barren planet in a system of three stars. Because of this, the planet is almost constantly in daylight; however, approximately every 22 years when the orbiting planets align, the desert planet is thrown into a pitch black prolonged night.
This eclipse lets the ravenous Bioraptors hatch and scours the planet in search of food. We don’t get a good look at the Bioraptors throughout most of the film, but we see the results of their killing prowess.
There is surely nothing quite like imagining trying to survive in an inhospitable alien ecosystem with an apex predator swarming through the air like bats, able to can carry off and tear anyone to pieces.
“Bio-raptors (being light sensitive creatures) live in deep dark caves, avoiding of any sunlight. Adult bio-raptors are large, winged predatory creatures. Their heads are shaped like a steel spinning top (extending left, right and upward; the upward extension is sharp almost like a long knife or guillotine). The head is complete with a set of large teeth, mostly incisors. Bio-raptors do not have eyes or a visible nose (though it is known that an olfactory system is present due to their acute sense of smell).”
– Reference Aliens Wiki