Peter is a fictional character in the Hey Arnold! TV Series.
Peter can be seen in the episode 'Synchronized Swimming' as one of the judges for the competition. Mr Simmons is notedly in the audience for the event.
He can be seen again in the episode "Rich Guy" where he is having dinner with Pearl Simmons (Mr. Simmons' mother.) Mr. Simmons however, is not with them. He also made a brief cameo in Hey Arnold: The Movie.