Dr. S is a self-taught cobra doctor from All Hail King Julien.
He first appeared in "That's Sooo Rob" where Rob wanted Dr. S to transplant some of King Julien's parts into him. Dr. S states that he can't be busted for practicing medicine out of a cave. Dr. S ends up beaten up by Clover.
In "The Phantom of Club Moist," Dr. S assists Rob in a plot to switch Rob's mind with King Julien's mind. Although it was only temporarily. Both of them were defeated by Clover as King Julien decides to spare them from Clover's wrath. In order to have his legacy help people, King Julien has Club Moist re-established as a hospital with Dr. S and Rob as the first doctors. Dr. S is pleased that he can finally practice medical procedures outside a cave. By the end of Maurice's story, Dr. S drops a stalactite onto Maurice's piano stating that the rule of the Club Moist Hospital states that there is no singing in a cave. Though Dr. S doesn't recall the other rules.
In "King Juli-END?," Dr. S examines King Julien and claims that he has a rare disease called Mad Horse Disease which there is no cure to. He also tells King Julien that he has one week to live.