Slimy Sami is Perfect Peter's so called 'pen pal from France' who tries to use Horrid Henry and get him in trouble. He tries to steal Peter's stamp album but Mum catches him red-handed, subsequently sending him home. He is voiced by Aidan Cook.
In Perfect Peter's Pen Pal, he was best friends with Peter until he turned on him and tried to escape with his stamps. He also had other pen pals in the past and were friends with them, though he revealed he turned against them as well. After he left Peter then mentioned that he’s coming back and Sami probably apologised for taking Peters Stamp Collection and decided to be friends again.
In Series 4, He returns and from Horrid Henry Eco Warrior, he helps Peter. He has moved to Ashton Primary School in Series 4 and was in Peter’s class.