Apophis is not a rival god competing for worship the way Set or other Egyptian deities are, and Egyptologists are careful to keep that distinction clear: he represents non-existence and chaos itself, an anti-force opposed to the created order rather than a god with his own cult, temple, or worshippers seeking his favour. What makes Apophis unusual is that the myth of his nightly attempt to swallow the sun god Ra as Ra's barque crosses the underworld was not treated by Egyptians as a story alone, told and left at that.
Surviving ritual texts, most importantly the collection known as the Book of Overthrowing Apep, describe actual temple ceremonies designed to magically assist Ra in the ongoing struggle, including priests reciting execration formulas, spitting on, trampling, and ritually burning wax or clay images of the serpent, timed to coincide with moments such as sunset or storms when Apophis was believed to pose the greatest threat. This means the myth had a genuinely enacted, ongoing ritual dimension, performed as needed rather than only recounted, on the understanding that failing to perform it could have real cosmic consequences, a level of continuous ritual engagement with a mythological threat that has few close parallels among the deities of surrounding Bronze and Iron Age cultures.