Mermaids looked like beautiful women from the waist up but had the body of a fish from the waist down. The could cause storms and were generally quite dangerous but some were known to be gentle and helpful to mortals.

The Mermaids of Ireland were more gentle than those of England and sometimes married mortals.

Mumpoker

See Nursery Bogies.

Muryans

This is the Cornish word for ant. It was believed that fairies became smaller and smaller each time they changed shape until they finally became ants and then disappeared.