Udug

The Udugi (Sumerian), later known in Akkadian as Utukku, were an ambiguous class of demons from ancient Mesopotamian mythology.

In external general features, he resembles all kinds of ancient Mesopotamian demons: a dark shadow, the absence of light surrounding it, poison and a deafening voice.

In a bilingual incantation written in Sumerian and Akkadian, the god Asalluhi describes the "evil udug" to his father Enki:

Oh my father, the evil udug [udug hoole], his appearance is evil and his height is tall,
Although he is not a god (dingir), his noise is huge, and his radiance [melam ] huge,
He is dark, his shadow is pitched. Black and there is no light inside his body,
He is always hiding, hiding, [he] does not stand proudly,
His claws drip with bile , he leaves poison in his wake,
His belt does not untie, his arms cover ,
He is filled with the purpose of his anger with tears, in all lands, [his] battle cry cannot be restrained. 

Types of Shadow demons:

• Mimma Lemnu (the term refers to both a spell and a shadow demon associated with witches)
• Hanbi (the personification of evil, the lord of all demonic forces of udug)
• Ardat Lily (shadow demon with features of a woman, a dog and a scorpion, a devourer of children)
• Vardat Lilitu (a shadowy vampire demon preying on children, originally disabled by Dingir in the first myths)
• Alu Lilu (shadow demon without a face)
• Pazuzu (shadow demon at the head of all evil spirits of the air)
• Mukil res lemutti (A shadow of demons that brings misfortune and is able to possess people, forcing them to turn into trapped animals)
• Namtar (infecting shadow demon, ally of Dingir Ereshkigal, whose task is to keep the demon Mimma Lemna chained in the underworld)
• Tiu (The Headache-provoking Demonic Shadow, Dingir's ally)
• Ahhazu (Demonic Shadow of Pestilenza, ally of Dingir Lamashtu)
• Kilili (shadow demon associated with owls, ally of Dingir Inanna)
• Labasu (the shadow demon present in the text of Nusku's exorcism)
• Abizu (Shadow demon responsible for spontaneous abortions and childhood illnesses)