The first phase of the withering begins when Bonnie, at the end of the first game, tries to attack Gabriel Miller. Gabriel then grabs a chair and throws it at Bonnie, hitting his right arm and knocking him down. Gabriel then attacks Bonnie's left eye with another chair while he's on the ground. Mangle starts chasing him, looking for a part that will tell the story of another character's withering in the next story. Continuing, soon after, Bonnie stealthily appears, using his ability to be the most silent and patient of the group, and attacks Gabriel, killing him. In other words, Gabriel was responsible for removing his eyes and breaking his arm. The second and final phase is when Bonnie is abandoned, ends up rotting, and his face falls off, precisely because of the aftereffects of the previous attack. And a detail: this attack also caused cracks in his foot, so when Fazbear brings him back to Parts and Service in the state place, they remove him permanently because he is cracked and wrecked, no longer useful. nothing. His face, though, is still kept somewhere.