She feels unpleasantly like she's under the microscope, and rather wants to avert her eyes, but something very Gryffindor in her makes her stare back.

She blinks at the mention of it's other uses. Right. The Dark Mark. It takes a lot of effort not to cast a pointless glance at his arm. Surely he must know more about it than she does?

"I got the idea from the Dark Mark, if that's what you're asking," she says- perhaps a little defiantly, refusing to be apologetic about it. She's not exactly proud of, well, copying off Voldemort, but it's the truth.