Ironically enough, she genuinely had picked those colors by coincidence...or something like it.

"I can see how that might prove a difficulty, indeed." She would know her own, but there were many others running about, and she had no confidence in their perspicacity. "A change is in order, then. So!" Medea's coat darkened to an even midnight black with a wave of Maleficent's hand. She did say she was a sorceress, after all.