I decided to go to the museum's website for information about some of these frogs. Here is the description of this bad boy:
Ornate horned frogs have voracious appetites, but they are not built for chasing down prey. They bury themselves in leaves or loose soil and pounce on small animals that blunder by. When harassed by a human or other large animal, these fearless frogs lunge and snap their huge jaws. Like little green bulldogs, they bite and hang on until pried loose.
Ornate Horned Frog
Size: Up to 7 inches
Food: Mice, lizards, birds, snakes, insects, other frogs
Range: Uruguay, Brazil, and northern Argentina
Habitat: Rainforests and pampas prairies
Life Cycle: A thousand or more eggs are attached to plants in water. The tadpoles have voracious appetites and often eat each other.
He kind of looks like a huge lump, so the description is pretty right on.