Ripley: Come on, Ash, I mean, the Science Department should be able to help us. What can we do to drive it?
Ash: Yes, well, it's adapted remarkably well to our atmosphere considering its nutritional requirements. The only thing we don't know about is temperature.
Ripley: OK, what about temperature? What happens if we change it?
Ash: Let's try it. I mean most animals retreat from fire, yes?
Dallas: Fire, yeah.