Kuman Thong (also referred to as Guman Thong) translates literally to "golden child" and is used to describe a child or baby spirit, revered by Buddhists and animists.
Effigies are made, traditionally from wood, but often featuring gold, which are then kept and treated well with regular worship, in order to bring good luck to the owner.
See below for a video of a traditional Kuman Thong being made:
Smaller charms can also be made that are worn around the neck as a good luck charm.
However, there is a dark and extreme side to the belief system, in which worshippers delve into the world of the occult.
The original, ancient form of the Kuman Thong would require a dead foetus, often surgically removed from the mother's womb. The foetus would then be taken to a cemetery, where a series of incantations were recited as the foetus was roasted.
Illegal practitioners have been known to coat their effigies in the fat of human babies to consecrate them.
The earliest mention of the belief in Kuman Thong can be found in the 18th century Thai fairytale of Khun Chang Khun Phaen, where the character of Khun Phaen acquires a powerful spirit by removing the foetus of his stillborn son from his wife.
The classic poem of Khun Chang Khun Phaen is known throughout Thailand (Bangkok Post)
The recent arrest has revealed that the ancient, illegal practices are still ongoing, catering to an international black market of the occult.
Chow Hok Kuen, the 28-year-old man who was arrested for attempting to smuggle the roasted foetuses, was looking to make around £24,000 from the sale and now faces a year in prison.
The foreign office has said it is investigating the case.