The antagonist is targeting the girls of South Park Elementary on the school's message boards and Kyle and all the girls believe Eric Cartman is the bully due to his previous bigoted and sociopath behavior. However, the guys realize that Cartman is not the troll after they destroy all his electronic devices, and the troll keeps targeting people anyway.
At the end of "Member Berries" it is revealed that Gerald Broflovski, Kyle Broflovski's father, is Skankhunt42 and not Eric Cartman, which means that Cartman is not guilty of the whole thing.
Gerald admits his bullying to his youngest son Ike since he knows no one would believe or understand him. He claims it is "guy" stuff and is harmless pranks photo shopping penises in women's pictures as a retribution for them not agreeing with his views. At the end of the episode, Skankhunt42 gets onto the international news after trolling a Danish website for Women with breast cancer.
While implementing in his internet trolling, Gerald likes to play hard rock music and drink wine.