Once the chaos had been sorted out, Snape and Lockhart stood in the middle of the hall. "I think I'd better teach you how to block unfriendly spells," said Lockhart.
"Shield Charm," said Leo to Marisa, rolling his eyes.
"Let's have a volunteer pair – Longbottom and Finch-Fletchley, how about you – "
Snape disagreed: Longbottom, apparently, would cause devastation. Instead, he suggested Draco and Potter. Lockhart agreed and the pair stepped forward.
Potter and Lockhart conferred for a moment (Lockhart tried to demonstrate something and dropped his wand) and then Draco cast: "Serpensortia!"
A long black snake shot out of the end of Draco's wand and slithered towards Potter.
"Why didn't you teach us that spell?" asked Marisa in an undertone as the snake raised itself to strike.
Lockhart pointed his wand at the snake: there was a bang, and the snake flew up into the air and hit the ground again. Hissing furiously, it slithered straight towards Finch-Fletchley, about to strike –
And then a strangled hissing stopped it in its tracks, and it fell to the ground, docile, looking directly at Potter.
Everyone gulped, and soon there was an ominous muttering filling the room. "What do you think you're playing at?" yelled Justin and stormed out.
"Explain later," said Leo quietly to Marisa, and then went over to speak to Draco.
"Potter's a Parselmouth?" asked Draco, shocked.
"Evidently," replied Leo, mind whirring as he considered the implications of this. If he was a Parselmouth, that greatly increased the chances of his being Slytherin's heir… "Does that mean he's – "
Draco picked up on the implication. "No – why on earth would he go around with the Mudblood if he was?"
"I hope you weren't talking about me," said Marisa coldly: unable to wait for Leo to explain later, she had decided to eavesdrop instead.
"No," said Draco quickly, "we weren't."
"What's a Parselmouth?"
"Look it up," snapped Draco. "I can't be bothered to explain these things to you. You should make an effort to understand our culture!"
Marisa rolled her eyes and walked away.
"I'm not sure… he could be just doing that to try and deflect suspicion… we can't rule anyone out without more evidence."
Draco, frustrated, glared at Leo. "Why can you never, ever, be certain of anything?"
"Because absolute certainty is impossible. Prove to me that the entire world is not an illusion created by a purple devil intent on tricking everyone and stealing their souls."
Leo didn't actually believe that certainty was completely impossible, but winding Draco up was far too much fun to let a perfect opportunity slip by.
"But that's just ridiculous! Of course it can't be true!"
"Prove it," insisted Leo, carefully hiding his smile from Draco.
"Well – how on earth am I meant to do that – it's impossible to prove that kind of thing – "
"Exactly. Therefore, it is possible that the world is an illusion."
Draco stared at Leo suspiciously, as if trying to find the gap in his logic written on his face, and then said "You must be mad!" Then he spun around and stalked off.
Leo grinned. Driving Draco mad was extremely entertaining.