"That's rich coming from someone who claimed to be a Slytherin." Kyle resisted looking at Professor Snape. He curled his hands into fists "I should have known you were a blood traitor as soon as the hat put you in Gryffindor bunch of muggle lovers." 

Snape had, at Kyle calling Siobhan a blood traitor, shifted. His eyes flickered between the two kids. They didn't know he could 'read' their minds, but the limited prep they had put into this made their reactions more real. Siobhan's tears sealed the deal.

"That's enough. McCarthy, for that comment you have dentition Friday." Kyle frowned. Snape had given him a dentition, interesting.

"I just meant that-" Kyle tried to protest.

"I don't care what you meant. You will have dentition with me promptly at six pm Friday night. MacFusty you too better be in my office promptly at six Friday night." Kyle fought back any other comments in case Snape decided the punishment wasn't good enough. "Now both of you go or you'll be late for Potions."