Not sure where best to let people know about "Instinct Arrow"

This player was in my champ select. He opened the conversation by saying that he would intentionally feed. Then flamed all of the players before forcing someone to quit. I know there is no way to report someone in game if a game is not completed. I also know that reporting people is difficult, if you are looking for actual actions. I figured I would put his name out there, in case someone else encounters him and they want somewhere to warn other people.