The will-o'-the-wisp can be found in numerous folk tales around the United Kingdom, and is often a malicious character in the stories.
In Welsh folklore, it is said that the light is fairy fire held in the hand of a púca, or pwca, a small goblin like fairy that mischievously leads lone travellers off the beaten path at night.
As the traveller follows the púca through the marsh or bog, the fire is extinguished, leaving them lost.
The púca is said to be one of the Tylwyth Teg, or fairy family.
In Wales the light predicts a funeral that will take place soon in the locality. Wirt Sikes in his book, mentions the following Welsh tale about púca:
A peasant travelling home at dusk sees a bright light traveling along ahead of him. Looking closer, he sees that the light is a lantern held by a dusky little figure, which he follows for several miles. Afterwards he finds himself standing on the edge of a vast chasm with a roaring torrent of water rushing below him. At that precise moment the lantern carrier leaps across the gap, lifts the light high over its head, lets out a malicious laugh and blows out the light, leaving the poor peasant a long way from home, standing in pitch darkness at the edge of a precipice.
This is a fairly common cautionary tale concerning the phenomenon, the ignis fatuus was not always considered dangerous.
There are some tales told about the will-o'-the-wisp being guardians of treasure, much like the Irish leprechaun leading those brave enough to follow them to sure riches.
Other stories tell of travelers getting lost in the woodland and coming upon a will-o'-the-wisp, and depending on how they treated the will-o'-the-wisp, the spirit would either get them lost further in the woods or guide them out.
Also related, the Pixy Light from Devon and Cornwall is most often associated with the Pixie who often has pixie led travellers away from the safe and reliable route and into the bogs with glowing lights.
Like Poltergeist, they can generate uncanny sounds. They were less serious than their German Weiße Frauen kin, frequently blowing out candles on unsuspecting courting couples or producing obscene kissing sounds, which were always misinterpreted by parents.
Pixy Light was also associated with lambent light which the Old Norse might have seen guarding their tombs.
In Cornish folklore, Pixy Light also has associations with the Colt pixie. A colt pixie is a pixie that has taken the shape of a horse and enjoys playing tricks such as neighing at the other horses to lead them astray.
In Guernsey, the light is known as the faeu boulanger, rolling fire, and is believed to be a lost soul.
On being confronted with the spectre, tradition prescribes 2 remedies. The first is to turn one's cap or coat inside out. This has the effect of stopping the faeu boulanger in its tracks.
The other solution is to stick a knife into the ground, blade up. The faeu, in an attempt to kill itself, will attack the blade.
The will-o'-the-wisp was also known as the Spunkie in the Scottish Highlands where it would take the form of a linkboy, a boy who carried a flaming torch to light the way for pedestrians in exchange for a fee, or else simply a light that always seemed to recede, in order to lead unwary travelers to their doom.
The Spunkie has also been blamed for shipwrecks at night after being spotted on land and mistaken for a harbor light.
Other tales of Scottish folklore regard these mysterious lights as omens of death or the ghosts of once living human beings. They often appeared over lochs or on roads along which funeral processions were known to travel.
A strange light sometimes seen in the Hebrides is referred to as the teine sith, or fairy light, though there was no formal connection between it and the fairy race.