The Trows of Shetland were in some respects very like fairies. They were for instance fond of music, though their preferred instrument was the fiddle rather than the bagpipes favoured by fairies in the rest of Scotland. They would sometimes lure a musician inside their hill where he would remain unconscious of the passing of time until he was released after a year and a day or longer.
In other stories, rather than entering the mound the fiddler rests outside, where he overhears the trows' own music. Several tunes are said to have been passed on in this way, including one from Vallafield and another known as the Hyltadans or Haltadans, dating back to the mid 17th century. According to tradition, a man from Culbenstoft was going towards the sea one night when he heard the trows dancing to a song he later wrote down. This is one of the simplest of The Trowie Tunes of Shetland, and the earliest. It must have begun as a song-tune before it was adapted for the fiddle, since the instrument only came to the islands in the 18th century.
The tune survived but not these particular trows, who carried on dancing too long and were caught by the sunrise. They were turned to stone - as a punishment - according to some sources, although this is probably a later addition to the story, referring to legends of human dancers in mainland Britain who suffered this fate for dancing on the Sabbath. The trows, however, were closely associated with the Scandinavian troll, traditionally said to be petrified by the sun's rays.
What remains of the dancers can still be seen at Haltadans; an outer circle of stones, originally standing but now fallen, and an inner circle of earth and stones. At the center are two standing stones (possibly there may have been a third) said to have been the fiddlers who played for the trows. The name of the tune, and the site, "Hyltadans" or "Haltadans," means 'halting dance'" trows were traditionally said to have a particular stumbling or limping way of dancing.