There is never a dull moment when it comes to nature's mysteries.

Humans will probably never discover all the species that they share the Earth with but there every once in awhile someone accidentally finds an animal or plant that looks like something out of a nightmare. The discovery of a two-headed shark off the coast of Australia back in 2008 is a perfect example.

Since then more and more mutant shark embryos are being found by fishermen and researches. Recently, Spanish scientists found a two-headed Atlantic sawtail catshark during an observation session. It was the first of it's kind born by a shark that lays eggs. Marine scientist Nicolas Ehemann also found one in the Caribbean Sea and prior to that Florida fishermen had their own sighting of a two-headed Blue Shark fetus.

The rise of these polycephalic sharks have had biologists scratching their heads. Some argue that the mutation may be caused by factors like viral infections or pollution while others attribute to the rise in inbreeding due to overfishing.

There aren't enough accessible specimens of mutated sharks for scientists to study so we won't know just yet what's behind this strange genetic occurrence. "I would like to study these things, but it's not like you throw out a net and you catch two-headed sharks every so often," said Ehemann.

So there you have it, you've got nothing to worry about because the numbers aren't growing at all and chances are you won't be seeing one on vacation anytime soon.