Apep's name was often incorrectly defined as he who was spat out. It was said that he had been formed by Neith, who had been the goddess of the ancient waters in the Ennead, from a length of spit she had spat at Nu, the god of the ancient waters in the Ogdoad. Some subsequent commentators speculated that Apep must have been an earlier creator, and chief god, thus explaining why he had so much anger towards Ra.
It was believed that Ra (the sun) each night passed into Duat and then battled with Apep, always winning except for certain days in which Ra is momentarily devoured, what the Egyptians saw as an eclipse.
Instead of being worshipped he was done the exact opposite and spat upon. Models would be made of wax and clay and then burnt, spat upon, and defaced.
Apep was a fifty foot long snake. He was black, orange, and a little bit green. Apep was very strong. He symbolized darkness, storms, night, the underworld and death. Ramses sixth tomb depicted him, having nine heads, representing the souls he killed. In some depictions he is shown being attacked by a cat. The cat represents Bast, the goddess of cats. Bast was Ra's 'Guardian', so to speak. Bast's job was to protect Ra on his trips through the Duat every night.
- The asteroid 99942 Apophis, an Aten-class asteroid, is named in its honour, because it was at Level 4 on the Torino impact hazard scale between 2004 and 2006.
- The name Apophis was given to the first major false god enemy in the sci-fi series Stargate SG-1
- The name Apep Heidemann was given to the major enemy in the Japanese manga Seraphic Feather.
- In the Yu-Gi-Oh! Trading Card Game, there is a snake-like Trap Card Monster called 'Embodiment of Apophis'. Considering the original Yu-Gi-Oh!'s Egyptian origins, this befits the context of the card game.