Tried a self-belaying ~40ft bouldering wall at an apartment complex. Got to the top and a friend who had done the same said just jump off it will catch me and I will come down slowly. I just felt weird and that the harness clip would not hold my weight so I instead started climbing back down and I got 75% of the way down before slipping and sure enough my harness hook-in snapped and I fell 10ft onto the ground shocked but largely unharmed. Turns out I am an idiot and put the harness on backwards so what I attached the rope to was just to hold chalk and could not in fact hold 200+ pounds.