On a nighttime walk in 2009, scientist Katherine Krynak spotted a well-camouflaged, marble-size amphibian that was covered in spines. But when she brought it inside, suspecting it was a new species, Krynak found a rather smooth and slimy critter.

"I was so mad at myself! I thought I had brought back the wrong frog," said Krynak, who was surveying amphibian species in the Reserva Las Gralarias.

She hadn't. When she tucked a small piece of moss in the frog's container to make it more comfortable before releasing it back into the forest, the spines slowly reappeared.

"It was shocking. Vertebrates don't do that," she said. Inspired by its spiky physique, she dubbed it the "punk rocker" frog.