Goblin Magic

Goblin magic is a form of magic practiced by Goblins. It seems to be performed non-verbally, meaning that these creatures don't need to incant a verbal spell to focus their powers. Although it hasn't been deeply explored, it seems this type of magic is used by Goblins mainly to play tricks and pranks on innocent people and to help them get what they most desire, gold. It's unknown how powerful it is related to the other kinds of magic (Troll magic, Sidhe magic and the magic of the Old Religion).

The main characteristics of Goblin magic are:
​
 * Goblins are capable of transforming themselves into small bright balls of light. Whilst in this form, they are capable of possessing another living being and controlling their body and thoughts. A Goblin also make the person that's under its power physically stronger.
 * The ability to change, with just a blink of their eyes, the effects of medicines and potions, giving them particular magical properties. The Goblin that had possessed Gaius gave Morgana, Uther, and Gwen an enchanted sleeping draught which caused them to suffer from flatulence. The Goblin also used another potion to cure Uther of his baldness (which he had caused, too). Another potion, that Gaius had secretly added to a flagon of ale which he then had served to Sir Leon and other knights, caused the man's face to be completely covered in boils. To force Sir Leon to pay a fortune in gold coins, the Goblin said that the infection had no cure and that the itching would become so unbearable and severe that the patient would be driven to madness.
 * Goblins can cast a glamour without an incantation. Arthur, who had understood that Merlin was saying the truth about the physician, was partially transformed into a donkey, given the animal's ears and made bray.
 * Goblin magic allows its users to perform telekinesis. The Goblin was able to throw a dagger against Merlin with a simple gesture of his hand and later to smash a pot on Arthur's head with a blink of his eyes.
 * Goblins have psychic abilities and can see deep into someone's heart, reading his or hers thoughts. This happened to Morgana, whose true nature was revealed by the Goblin.