The Sleer is a mysterious being that resides in the graveyard’s barrow grave. Bod only sees the Sleer once; it’s huge, with three heads featuring indigo designs and the body of a snake. It speaks in a hissing, slithery voice, and Bod can also hear its body slithering around the walls of the barrow grave’s chamber. According to the Sleer, a mysterious “master” left the Sleer in the grave to guard the treasures—a knife, a cup, and a brooch—though the Sleer never explains who the master is or where he or she went. Bod is afraid of the Sleer at first, but he realizes over the years that the Sleer gives good (if cryptic) advice and can’t hurt him, so long as Bod leaves the treasure alone. Since the Sleer is on the lookout for a new master to serve and protect, Bod uses this to his advantage when Jack pursues Bod and Scarlett into the barrow grave. Jack greedily thinks becoming the master will allow him to start a new order like the Jacks of All Trades and access the treasure in the barrow grave, so he agrees to be the master. But instead, the Sleer wraps itself around Jack, pulls Jack into the walls, and magically imprisons him in the grave.