Noose

I wouldn’t really classify this as a weapon per say but it was seen in 2004’s Alien vs Predator. The Scar Predator uses some form of wire to kill one of the mercenaries when the team is walking down a corridor. The Predator hangs it down from above, the mercenary’s head gets caught in it and the Predator pulls him up. Interestingly, the wire appears to be cloaked too.

In a similar vein, in AvP Requiem, the Wolf Predator hangs up Dallas with some rope but doesn’t kill him.