There are more than a few vacant cells in Arkham Asylum that have random things painted on the walls. By the time you notice the Riddler’s cell, it’s nothing new. Only, instead of handprints, his cell is marked in footprints? That’s slightly more unsettling and far more unexpected. Props to you, Rocksteady Games, for making even the little details in Batman: Arkham Asylum really awesome. I hope Arkham City has the same level of creativity.
(Did he draw all the question marks with his toes?)