It's another example of Gotham City's insane architecture. Like, instead of going for a classic demon/devil gargoyle, or a bat-like gargoyle, this particular sculptor decided to go with some sort of horrifying giant bat-monster with an exposed rib-cage, hook-like claws and fangs that look like shark's jaws. This image, by the way is a splash page, and incredibly well-designed in general. The gargoyle's cool, as is the depiction of Batman and The Riddler, their similar posture demonstrating the way they think alike as they compare their cracking of the complicated clues in the case they're working on. I like the little inset-panels, breaking up the dialogue and keeping the eyes dancing over changing art despite the use of a splash-image, and the way their borders make them look like little case files.
And hey, not only does the gargoyle look cool, as you can see from this panel, it's also functional, hiding a gutter to move rainwater off the roof and away from the building:

You know, I liked this Guillem March character the first time I saw his art, and I think I like his work more and more the more I see of it.

