One of the most fascinating monsters in human cultures is the ghoul — here, you see a particularly nasty one about to be done in by the hero Shah Namah in a 10th-century Persian manuscript. The legends of ghouls extend back in time to the pre-Islamic Arabian Peninsula, but have persisted into modern times, much like the cryptids Bigfoot or the Loch Ness monster.
In the Ancient Mesopotamian Akkadian language, the word “gallu” was related to the Arabic “ghâl”, which can mean “to kill,” and explains the etemology behind the word “ghoul.” The earliest accounts suggest that ghouls were often female monsters who could change shape to destroy their prey. Some traditions of Muhammad state that he gave advice to people about how to thwart ghouls, which often entailed reciting holy words like the name of God or the “Throne Verse” (Q2:255) from the Quran.
The Bedouin nomads of the desert were particularly influential in sharing stories of ghouls. They may have actually been the main contributors of these legends to the urban areas of the Arabian Peninsula. This makes sense, given the fact that many accounts mention ghouls lying in wait in the desert to attack and eat unwary travellers.
The collection of Medieval stories known as _The Thousand Nights_ have several folktales featuring ghouls. Unsurprisingly, translations of _The Thousand Nights_ changed what ghouls looked like from the Arabic original. The late 18th-century Orientalist Antoine Galland, for instance, straight-up invented the idea of ghouls as monsters living in graveyards that ate corpses. He probably got Arabic legends of hyenas mixed up with ghouls. But that had a big impact on Western cultures, which tended to interpret ghouls as carrion-devouring monsters.
Sources: “The mythical ghoul in Arabic culture,” Jan 2009, Ahmed Al-Rawi, _Cultural Analysis 8: pp 45-69, published by the University of California. Image is “Shah Namah, the Persian Epic of the Kings,” library reference: Or A. WMS.Per.483, the Welcome Collection gallery