Mystique once drugged and kept Dazzler in a coma, using her genes to make up the mutant hormone drug, as well as impersonate her within SHIELD and taking over her life.
Not sure a simple blast and letting Mystique fall from a building before rescuing her makes it even, but whatever floats Dazzler’s boat.
Amazing though that a group of young and barely trained teen mutants managed to capture Mystique.
From – Uncanny X-Men Vol. 3 #34
