Rotting disease was a malady spread by the tesfli piercer, an insect indigenous to the planet Gorsh in the world. If a person bitten by a tesfli piercer did not get treatment, the affected limb would rapidly swell and then become a discolored black. The flesh would then disintegrate, making the limb unusable. The disease was most severe when a person received many times bites, even dozens or hundreds, if they came across a swarm of these insects tesfli piercer.