The tales of sea serpents that terrified seafarers in days of yore may have been inspired by the mysterious oarfish. This creature gained its name from the two delicate fins that extend down from beneath its head, which resemble long oars. However, while the function of these odd "oars" isn't yet known, experts say they're too flimsy to help with locomotion.

The oarfish in this picture was stranded in Mexico, and it appears to be about 20 feet long. Pepperell writes that there have been reports of oarfish that measure up to 55 feet long, but these unsubstantiated accounts are most likely just fish tales.