"Filthy fucking Mudblood."
Something snapped in her. He actually saw it; the flicker of something dark in her eyes, something almost feral. He tried to shift but another wave of nausea from Granger’s attack flushed his brain, and he squinted his eyes to try and focus on her.
"Mudblood," she repeated in a husky hum, raising her wand slightly.
He spat out a startled grunt as she stabbed her palm with the tip of her wand, dragging it across her flesh to create a thin red slit. She stalked into the bathroom then, nearing him and displaying her fresh wound. He watched with a morbid fascination as a ribbon of blood glided down her middle finger, and two ruby pearls rained down to splat against the ivory floor by his feet.
"You find this filthy?" Hermione questioned with a wavering tone, crouching down so she was at his level. "You think my blood is filthy?"
"DO YOU?" the witch yelled, leaning forward to snatch his hand.
"What the hell are you doing?" he asked, accepting that he was starting to panic in response to her dubious movements. "Granger, what the fuck?"
She quickly drew a similar slice across his hand, and a combination of his shock and still-sluggish reflexes didn’t allow him to interfere as she slammed their palms together with a wet slap.
"There," Hermione spat, holding their twisted and sticky handshake firm as she spoke. "Now your blood’s filthy too!"