Blue Men of the Minch
The Blue Men used particularly to haunt the strait between Long Island and the Shiant Islands. They swam out to wreck passing ships, and could be stopped by captains who were good at rhyming and could keep the last word. They were supposed to be fallen angels. The sudden storms that arose around the Shiant Islands were said to be caused by the Blue Men, who lived in under-water caves and were ruled by a chieftain.