Oh, man, what was that film?!?
I saw this one film, back in the 80s...it was one of those super-cheesy blonde-commando films--you remember the type? Where you discard your sense of belief that some busty blonde chick could actually be a super-ninja-deathtron-waste-o-matic killing machine, bent on vengeance because her lover/boyfriend/meat puppet got killed by the mafia/rival gang/hot-dog vendor, solely so you can see her put camouflage paint on her chest.
Anyway...oh, knife content...that's right. Anyway, at one point, she uses this hollow glass "Death Knife." A blade roughly the size and shape of Hibben's Rambo Bowie, but made of hollow glass, and filled with acid. The idea was that she'd stab someone with it and snap the blade off, adding insult to injury...
Of course, the thing most injured by this blade was my sense of believability...I mean, she carries this thing through the jungle, gets beat within an inch of her life, and it only breaks after she lodges in some guy's chest...not to mention that, despite its being about 16" long, during the compulsory strip search scene, she manages to keep it hidden from her captors. I can see it now...
Guard 1: We've finished the strip search, sir!
Guard 2: Very well. Nice posture, for a prisoner...
Guard 1: What?
Guard 2: Her posture. It's very good. Nice, straight back. Odd, how she walks, though.
Guard 1: I, uh...hadn't noticed...I never got that far down...
Guard 2: Oh. I DO see what you mean...maybe we should do a cavity search...?
Guard 1: Good idea...AAAAAAAAIIIIIIIIIIIIGGGGGGGGGHHHHHHHHHHH!!!!!!
Still, it's an interesting, if not highly pragmatic, idea. Perhaps a cavity on the blade, where you could put an ampoule of poison or something...