Okay, no one is going to guess this....the answer is "a parachute". They fail about once every thousand uses.
"Risers" are the lines that connect the harness to the canopy, and "toggles" are the loops or handles that you grab and pull to steer the chute.
I never got to 1000 jumps, but I have a couple of hundred under my belt. I had some mishaps, but I never had a actual chute malfunction.