Some props just look cool, while others are completely functional. Well, when looking at the movie Aliens watching those dorky looking marines blast away the slimey crawling aliens it was only a matter of time before someone decided to replicate the weapons they where using. And replicate them they did, fully functional pulse rifles from the movie Aliens (granted, the grenade launcher has been replaced with a shotgun). Check out the instructions, part list, and price here. If you don't want a real gun, they have instructions on creating an AirSoft varient along side the real deal.