The Muc-sheilch or Muc-sheilche is a loch monster

Lake monster

A lake monster or loch monster is a purported form of fresh-water-dwelling megafauna appearing in mythology, rumor, or local folklore, but whose existence lacks scientific support. A well known example is the Loch Ness Monster. Lake monsters' depictions are often similar to some sea monsters...

 reported to live in Loch Maree

Loch Maree

Loch Maree is a loch in Wester Ross in the Northwest Highlands of Scotland. At long and with a maximum width of , it is the fourth largest freshwater loch in Scotland; it is the largest north of Loch Ness. Its surface area is ....

, and its neighbouring loch

Loch

Loch is the Irish and Scottish Gaelic word for a lake or a sea inlet. It has been anglicised as lough, although this is pronounced the same way as loch. Some lochs could also be called a firth, fjord, estuary, strait or bay...

s.

Mr Banks of Letterewe

Letterewe

Letterewe is a large estate of several tens of thousands of acres on the north-eastern shore of Loch Maree, South-East of Poolewe, in Wester Ross, Scotland. It is one of the wildest, most remote and least populated areas in the United Kingdom....

 tried at great expense to drain Loch-na-Bèiste near Aultbea

Aultbea

Aultbea is a small fishing village in the North-West Highlands of Scotland. It is situated on the shores of Loch Ewe, about 30 km west of Ullapool. The village has two hotels, the Aultbea Hotel and the Drumchork Lodge Hotel, which won the accolade of top whisky hotel in the world in 2006...

, in the 1850s, but failed. He also tried to poison it with quicklime. Loch-na-Bèiste is Scottish Gaelic for "loch of the beast", beast often being used for a loch monster in Ireland

Ireland

Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

 especially. Seilch would appear to be cognate with selkie

Selkie

Selkies are mythological creatures that are found in Faroese, Icelandic, Irish, and Scottish folklore....

; muc generally means a pig

Pig

A pig is any of the animals in the genus Sus, within the Suidae family of even-toed ungulates. Pigs include the domestic pig, its ancestor the wild boar, and several other wild relatives...

, but is also applied to whale

Whale

Whale is the common name for various marine mammals of the order Cetacea. The term whale sometimes refers to all cetaceans, but more often it excludes dolphins and porpoises, which belong to suborder Odontoceti . This suborder also includes the sperm whale, killer whale, pilot whale, and beluga...

s as muc-mhara (sea pigs).

It has been suggested that it may be a large eel

Eel

Eels are an order of fish, which consists of four suborders, 20 families, 111 genera and approximately 800 species. Most eels are predators...

.