Wither Sickness is a long-lasting variant of the Wither Status Effect. It is inflicted by the Wither Storm.
The Wither Sickness is inflicted if a person remains in contact with the Wither Storm's tractor beam or tentacles for too long.
When a person is inflicted with Wither Sickness, he/she slowly gets weaker, and the affected part of the body slowly turns purple. The disease then slowly spreads to the whole body, and the person slowly withers away, causing inability to think or move.
Sometimes, a person inflicted with Wither Sickness does not get any aforementioned symptoms of the disease, but instead also starts to suffer from amnesia and loses his/her memory. It still, however, causes the person's skin to turn darker, as well as changes their pupils to red.
Unlike the regular Wither Effect, Wither Sickness does not wear off over time and is more lethal. The only known treatment for Wither Sickness is to destroy the source, i.e. The Wither Storm. It's unknown if anything else can cure Wither Sickness.
- Gabriel/Petra (whoever Jesse chose to save in Episode 1) was infected with a rather strong Wither Sickness for being caught in the tractor beam for only a relatively short time, considering that Jesse, who was caught in tractor beams and touched the Wither Storm's tentacles several times, was never infected with Wither Sickness.
- Gabriel mentioned in "Assembly Required" (determinant) that he had contracted Wither Sickness before in his travels, but it "always wears off", proving that the Wither Sickness given by the Wither Storm is not the same as the standard sickness.