Once upon a time there lived a frog, but no one every saw a frog during that time.
One day a traveler was walking by when he heard a strange noise. He walked closer to it and found the frog. He was amazed by its looks and decided to bring it home.
When he brought it home he told his wife about the discovery, she was confused. How were they supposed to keep it? They knew nothing about its needs. But the traveler had a plan. He would bring the frog to the king and hopefully sell it
When they arrived at the castle the king was already willing to buy it. He thought it would be his immortal pet since it doesn't drown, and can go on land.
He happily bought the frog and gave the couple 50 golden coins. He named the creature frog, after the person who brought him the pet, Frogert.