Amphibian horror isn't a movie type, but on this proof perhaps it should be. Harvard biologists have described a strange, hairy frog with cat-like extendable claws.
Trichobatrachus robustus vigorously breaks its own bones to produce claws that puncture their way out of the frog's toe pads, most likely when it is threatened.
David Blackburn and colleagues at Harvard University's Museum, think the ghastly behavior is a defense mechanism.
Some other frogs have scrawny spines that assignment from their wrist, but in those classes it appears that the bones grow through the skin rather than pierce it when needed for defense.
The researchers state there are salamanders that strength their ribs through their skin to produce protective barbs on demand, but nothing quite like this mechanism has been seen before.
The characteristic is also found in nine of the 11 frogs belonging to the Astylosternus genus, most of which live in Cameroon.