Had a possible idea for Salazzle where she would meet the MC during his journey to get a legendary but when she tries to use charm and pheromones' on him it has no effect at all. The side scene would be her hunting him down since she has always been able to get the male she targets. Turns out the MC is immune to charm and sex pheromones' since he is always ready to have sex at the drop of his pants and loves/lust all female Pokémon already so can't charm what is already charmed to all. The MC remembers this when he sees perfume with her pheromones' being sold.
She could also not stop trying to get the MC since he is the first male not to be effected by her and she will not tolerate that at all since she considers herself queen of the Salazzle and having the only male in the world immune to the pheromone in her harem would be her crowning achievement. So she would pop up at the next region some how and its not until she sees the legends in his harem that she has no chance of getting him.