(Sorry if this was a joke that went over my head and not an earnest question)

Afaik its a strategy to scare off predators. The general idea goes like… predators dont want to get stung --> predators less likely to eat wasps --> fly pretends to be wasp --> predator less likely to eat fly for fear of being stung. en.m.wikipedia.org/wiki/Mimicry here is a Wikipedia page if you feel like reading a much better longer description written by people who know a whole shitload more about biology than I do.