Early modern South Scandinavian folklore tells of the Gravso (grave sow), also called Gloso (glowing sow), Glumso (gloom sow) or Church Sow when sighted near a church.

First mentioned by a Copenhagen priest in 1587, the Grave Sow is described as a large boar or pig, often with long bristles and sometimes headless. Her eyes are red or glowing. Some stories tell of the back of the Grave Sow being razor sharp and able to cleave a man in half if the sow runs between his legs. She is often seen near the churchyard but can also be found in other places like near highways. Sometimes she is followed by a farrow of seven or twelve piglets.

The Grave Sow would come out at night, especially on dates considered magical. Seeing or even hearing the Grave Sow was often considered an omen of death or calamity and people who saw the her sometimes fell sick or lost their minds. Some stories tell of the people and horses being spellbound by the sow and suffering memory loss. Some accounts tell of the Grave Sow being especially dangerous to people carrying pouches made from pig bladders or clothing made from pig leather.

The Grave Sow has many similarities with other ominous revenant animals connected to churches but unlike creatures like the Hel-horses which legend has was horses that had been buried alive and sacrificed during construction of the church, the Grave Sow was believed to be the spirit of an unbaptised illegitimate child that had been born in secrecy and buried. It followed that a Grave Sow could be laid to rest by finding the remains of the child and given them a proper Christian burial. Common for many supernatural phenomena of the day, the Christian god was believed to be able to protect believers from the Grave Sow, like in one story where a peasant makes the Grave Sow disappear by reciting the lord's prayer.