I wasn't sure if this is considered a sci-fi weapon or an "other" weapon, so I'll just post it here.
The Combistick is a retractable spear-like weapon used by Predators. It can be thrown or used as a staff. The Predator recieves it once it finishes training and shows itself worthy to fight Aliens. If a Predator breaks his Combistick, he commits suicide (talk about fail)