/cgl/ - Cosplay & EGL

I want to make Black Knight from Monty Pyton. I think detachable arm and one leg at the knee to make people laugh.
Does anyone has any ideas about making a leg stump?
Arm one is easy, i can tie real one to my back, use magnets and make prop fall of with specific motion.
When I search for info all i find are cosplay guides for real amputees. I fear that if i simply bend my leg and tie it up for a longer time it will hurt like hell. I don't even know if it is feasible, though vision of jumping through the crowd on one leg is exciting.