One of my favorite frogs! Spent some time specifically looking for it. Managed to find two near Cobá, in Quintana Roo (in the Yucatán peninsula). This frog hides in holes in lime stone and tree trunks, and makes use of its flat head to block the entrance. This type of defense is known as phragmosis.
I agree! From the frogs in Yucatán, the one in this picture and the Mexican burrowing toad (Rhinophrynus dorsalis) are the coolest looking (in my opinion). I have looked and looked for the burrowing toad but I have never found one.