The demon Mosacus appears in the grimoires The Cambridge Book of Magic, The Book of the Office of Spirits, and The Book of Oberon
From The Book of Oberon, Dan Harms edition:
Mosacus
Mosacus appeareth in the form of a giant with the snout of an elephant with fiery eyes, having two heads in his breast, the head on the right breast a dog's head and on the left breast the head of an ass, and in the midst of his two arms on every arm the heads of two bloodhounds, and in his right arm a crook in a compass of a sickle, but he hath another as it were coming forth from that. He hath two eyes in the midst of his belly, and at his knees the heads of two bloodhounds. His hands and feet like the feet of a goose, but being commanded, he appeareth like a child with a red head. He giveth answers truly to questions.
This demon has head of the creatures Donkey Dog
This demon has snout of the creature Eagle
This demon later appears like the creature Captain