She appears to have had a very strong connection with the Theban area and might have even been considered a personification of that city. In the theology of Thebes, she was thought to be the mother of Osiris and therefore her afterlife associations are clear in the funerary texts in which she appears. 

Opet was usually depicted as some sort of combination of hippopotamus, crocodile, human and lion, though her hippopotamus aspect is dominant. She was represented as a female hippopotamus, usually standing upright on legs which have the feet of a lion. In this guise, her arms are usually human in appearance though they generally terminate in leonine paws. Sometimes she was depicted with the swollen belly of a pregnant woman and with large pendent human breasts. Her back and tail were those of a crocodile and sometimes this aspect was emphasized by a complete crocodile stretched over her back. 

Opet was only one of several goddesses, including Taweret, Reret and Heqet, who could take the form of a hippopotamus. All of these goddesses were associated with pregnancy and protection, and they were often difficult to distinguish from each other, not only in their form but also in their characteristics. 

Sometimes her depictions appear to be apotropaic in nature, and the vignettes of funerary papyri such as Spell 137 of the Book of the Dead, the goddess is shown holding a torch and lighting incense cones to provide light and heat for the deceased.

Though dating to the Pyramid Age prior to the rise of Thebes as an important Egyptian city, she was particularly venerated in that city where her temple just west of the temple of Khonsu was an integral part of the Karnak complex, even though it was a fairly late addition. In fact, it was on the ground that her temple sits, according to Theban beliefs, that she rested after giving birth to Osiris. Interestingly, while she even appears as a protective figure on the back of a statue of a 17th Dynasty ruler, in most areas of Egypt there appear to be no cult centers associated with the goddess.

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