Sseraj
Sseraj, or Sams, or Dr. John, is an administrator and Gmaas's pet. He was named Dr. John by his 1466 Pre-algebra class. He enters every class by posting a meme and announcing "I have arrived!" (EDIT: This is infrequent now; he instead posts a relevant caption to the picture of Gmaas he posts, see below). Often people disappear after posting a caption. A pet of Gmaas, he has become quite famous among the AoPS community. He often pops in on other classes and posts a photoshopped (or maybe it isn't?) picture of Gmaas. Sseraj has an MA in Gmaasology. For more information about sseraj's owner, see the Gmaas page.