Imagine a creature that can extend its bones through its hands as deadly claws. No, it’s not a rip-off of Marvel Comic’s superhero Wolverine. We are talking about a true-to-life marvel of nature known as the horror frog.

Found in Central Africa, the horror frog (Trichobatrachus robustus) is also known as the hairy frog or Wolverine frog. It gets the “hairy” part of its name because of the hairlike projections on the body of a mature male. The “horror” and “Wolverine” descriptions are the most fascinating.

When attacked, the frog is able to break the bones in its toes by a sharp and powerful contraction of its muscles. In the process it pulls the broken bones downward, through the skin, making the sharp points of the fractured bones emerge as claws.

The claw breaks away from a small piece of bone (see arrow) at the tip of the frog’s toe. Source: New Scientist

While other vertebrates have claws as defense mechanisms, the horror frog stands alone is the manner of producing its claws, as well as their composition. Unlike the claws of other animals, the claw is actual bone and not keratin.

The phenomenon of the self-made bony claws has only been observed in dead specimens, so researchers are unsure what happens after the danger to the frog has passed. They speculate that the claws retract back into the body when the frog relaxes, much as Wolverine’s do when he is no longer in danger.