This arete is what most people climb when they think they are on When I'm On My Own. It is missing from the guidebook, but perpetually caked with chalk and was once vandalized by some idiots with a blowtorch. A foot-long piece of stone dropped off the arete thanks to their carelessness.
Sit start the short arete and layback to the top, making use of the crimps on the left face, and also maybe a few high crimps on the right side. Grab the lip and mantle up.
Right of The Professor and When I'm On My Own and left of Another World. The easiest way off the boulder is to scramble down between Jaws and Hobbit Hole.