In order to gain favor with Sebastian Shaw and the villainous Hellfire Club, the mutant Mastermind used his mind control powers and a device from Emma Frost to slowly corrupt X-Man Jean Grey, aka Phoenix, and convince her she was his wife. She turned on the X-Men and (briefly) became Black Queen of the Hellfire Club. Cyclops almost getting killed broke Mastermind's control and the X-Men escaped the Hellfire Club, but then...Jean lost control of the Phoenix Force and became the Dark Phoenix.
She only appears like this for maybe a dozen panels (making for a tough training), but it made an impression on a young reader. Chris Claremont, partly responsible for a generation of mind control and corruption fetishists.
Backup location: https://huggingface.co/ottopilot/LadyJeanGrey