Ann Turkel refused to let any of the fake creatures spew blood or vomit on her, like they did to most of the other cast members. So Fred Olen Ray slipped a tube into a baby monster for the scene in which the actress wrestles with the creature. As they fought, Ray had an effects guy shoot "alien vomit" into Turkel's face. Luckily, she had a great sense of humor about it and didn't get upset.
This was Fred Olen Ray's highest-budgeted production at the time, coming in around $2 million.
Fred Olen Ray said he wrote the script in 1984 but put it away thinking no one would want to make it. Then he started showing it around in 1987 and was surprised at all the actors who read it and wanted to be in it.
Fred Olen Ray said this was the most effects-laden film he'd made at that point.
The creature is very similar in appearance to the creature in Alien, le 8ème passager (1979). It attacks by grabbing onto the mouth of its victim before entering the victim's body. It bursts out of the chest of the victim. When the creature opens its mouth, another extension comes out of the mouth and opens its mouth.