Pim Diffy (born 2109) is Phil's younger sister. She is a 7th (Season 1) / 8th (Season 2) grader at H.G. Wells Junior/Senior High. Pim was a mischievous girl who was constantly up to no good and was even prone to megalomania.Pim was especially known for liking to pull pranks on people, mainly on Phil, Debbie Berwick and Vice Principal Hackett. Pim tried to make Phil miserable whenever she could. She hung out with a young boy "Li'l Danny" Dawkins". She also tried to avoid Debbie Berwick and Candida. Repeatedly in the show, she looked for ways to dominate the world, and universe. Even though Pim often caused trouble for Phil, and has a tough attitude, she also cared about her brother but kept it hidden most of the time. Pim is two years younger than Phil.