It's possible you may be thinking of something else, such as:
* The Percy Jackson series itself: It features a wide array of Greek mythology creatures and gods, including bees. However, there is no specific "mythology bee" linked to Percy Jackson.
* A fan-made creation: Fans of the series often create their own content, including characters, creatures, or events. Perhaps you came across a fan-made "mythology bee" in a fan fiction or online community.
If you can provide more context about where you encountered this term, I might be able to offer a more specific explanation.