The Mester Stoor

According to Orkney folklore, the Mester Stoor Worm was a huge dragon that terrorised the people of Scotland. The dragon was known as "one of the nine curses that plagued mankind".
The Stoor Worm's breath was poisonous to any living thing, and he destroyed ships like eggshells. With his massive forked tongue he could sweep entire cities into the sea or crush the largest castle, sucking every living thing into his huge mouth.
When the Stoor Worm lay with his head near a kingdom, the people of that unfortunate land had to satisfy his hunger. Every Saturday he would wake, open his cavernous mouth and yawn nine times. He would then demand a meal of seven maidens.
The mighty dragon was eventually defeated by an unlikely hero, a farm boy by the name of  Assipattle, who was swallowed by the worm, but managed to set fire to it with a bucket of smouldering peat he had been carrying. As the dragon died and fell to the sea, he struck  with such force that he created a huge rift that became the Baltic Sea. His body became Iceland and his teeth the Orkney, Shetland and Faroe Isles.