Disclaimer is in chapter 1.
"Get between the girl and the snake," Wednesday instantly ordered, her wand leaping up, "And close your eyes unless I say otherwise!"
"Our eyes!? What about you!?" Ron blurted.
"My family doesn't petrify easily."
"Amen to that," Xander muttered, eyes slamming shut. "I've seen stuff at their place that would scare the venom out of this thing, trust her."
"Trust her?" Ron moaned, "You're telling me that our lives are depending on someone who can scare a bloody Basilisk, and 'trust her' is the best you come up with!?"
"Shut up, Ron!" Harry snapped, "Do what she says, that thing doesn't sound happy."
"It's insane." Wednesday's voice spoke up again, "As you would be if you were locked for your entire life in a hole like this, subsisting on vermin and magic. Alexander, straight ahead of you, slightly up. Bone splitter."
"Difindo Ossi!" Xander snapped, his wand dancing out. "Did I hit it?"
"No, but you made it turn around."
"I'll take the consolation prize."
"Where is it!? Where is it!?"
"SHUT UP RON!" Xander and Harry snarled together.
Contrary to her appearance, Wednesday Addams was worried. It was true that she wasn't susceptible to petrification, and even the Basilisk's killing stare would have diminished effect on her, but neither did she have access to anything that would seriously injure the great snake. She watched it as it moved around them, staying mostly to the shadows, but noted that the thing was larger than she'd thought. It was certainly as old as the legends said, and judging from its insane rambling had been locked down here almost the entire time.
For a moment she wished that she were a Parselmouth, rather than just had the gift of tongues all Addams had, but set that thought aside. The snake was quite simply mad. There would be no bargaining with it.
"You're only prolonging the inevitable." Tom Riddle said, shifting his attention to the Addams scion. "Mere students have no chance against a Basilisk, let alone one this powerful."
Wednesday ignored him, though she would much rather have cursed him. "Potter, Weasley, do either of you know any useful spells?"
Silence.
"What would be useful?"
"Oh lord, we're dead." Xander moaned.
"Hey!" Ron bristled, eyes still shut. "We can take you anytime you slimy snake!"
"With what? Rictusempra?" Xander countered.
"This is not helping."
"Sorry." Xander said, noting the tone in her voice.
"We just have to hold on," Harry spoke up, "Dumbledore will find us!"
"We're in the Chamber of Secrets, Dude!" Xander countered, "If he didn't find it fifty years ago, what makes you think he'll find it now?"
"Dumbledore is a stupid old fool," Tom Riddle's voice said smugly. "Accept your fate, you are already dead."
"SHUT UP!" Harry snapped, "Dumbledore is a great wizard! The most powerful one alive! He'll find us, and if he doesn't he'll still stop you!"
"You're a deluded child...!" Tom's voice began, only to be cut off when a pure sweet song cut through the air, softening all other noises in the chamber. "What!?"
"It's Fawkes." Wednesday said, eyes climbing to the bird as it circles. "The Headmaster's Phoenix. Watch out, Harry! It's dropping something."
Harry flinched as something landed on his head, but kept his eyes shut. "What is it?"
"Hello again there, Mr. Potter."
"H... Hat?" Harry asked, feeling the rumpled cloth on his head.
"Indeed, The Headmaster's birdy thought you may need something from me. Just a moment now and all will be clear."
Wednesday's eyes widened as she watched the Phoenix turn on the Basilisk, slamming into its eyes and scratching viciously. "I think you can open your eyes now."
The other three blinked, looking around, and soon found themselves enthralled by the battle in progress. The Snake's eyes were destroyed by the bird's assault, but it retaliated with a vicious twist of its body and slammed the phoenix across the chamber.
"Fawkes!" Harry screamed out, charging forward.
"This is the Headmaster's help?" Tom asked dryly. "A battered old hat and a crippled songbird. Even with its gaze you stand no chance against the basilisk!"
Xander and Wednesday had stepped forward, ignoring the blathering memory, and were raining bone splitter curses down on the large snake with depressingly little effect.
"How the hell do you kill one of these things!?" Xander yelled.
"The crow of a rooster," Wednesday replied between curses.
"Oh great." Xander muttered, "And we didn't bring one of those with us WHY!?"
"Someone killed them all weeks ago, there are none for miles."
"Figures."
As they bantered back and forth the snake had decided to take the fight to the two main threats, twisting violently as it rocketed across the chamber directly at them.
"We should move." Wednesday declared quietly as the snake closed the distance in mere seconds.
"Right with you!" Xander yelled, diving into her as the Basilisk drove straight at the Addams girl.
Wednesday sprawled out of the way, leaving Xander in her place as the snake reared up, its mouth opening wide to reveal gleaming and dripping teeth.
"Difindo Ossi!" Xander let out, wand leveled at the snake's mouth.
The Basilisk let out a roar of pain or rage loud enough to shake the world and began to violently curl around on itself as the spell struck on its upper fangs and split it from the beast's mouth. Xander stared stupidly at it for a moment until Ron and Wednesday grabbed him from behind and yanked him out of the way of the mass of muscled coils.
"Whoa!" Xander muttered from where he was sitting on the ground, "Did you see that?"
"Very nice spell, too bad you forgot to move afterwards," Wednesday told him dryly.
"Yeah, mate," Ron muttered, "A bit thick, that."
Xander shot him a dirty look, but was distracted by the snake getting its act together again and rising up to strike at them.
"We're boned."
As it crashed down, however, Harry dove in between them with a sword in his hand, driving it up into the snake's mouth and through its brain pain from the underside. For a moment it seemed to pause, then the huge bugger crashed down on Harry, practically burying him and crushing down on the others.
"Mate!" Ron yelled, lurching to his feet, pushing himself free of the coils.
Xander groaned from where he was pushed into the ground, dragging himself out from under the huge serpent, and glared at Wednesday who had somehow managed to be in the one spot the snake didn't hit.
"How do you do that?" He asked the serene looking Addams, spitting out blood from a split lip as he bled from multiple scrapes.
"Do what?" She asked calmly.
"Never mind." Xander sighed. "Yo, Ron! Harry ok?"
There was a long silence.
"Ron!?" Xander started climbing over the snake, stopping when he spotted Ron kneeling over Harry. "Jesus, Harry you don't look too good."
The black haired boy smiled weakly back, "Thanks a lot."
Xander's eyes followed the blood trail on the other boy, to where the Basilisk mouth was closed over his arm, and saw the tooth that had penetrated Harry's arm.
"Damn." He whispered.
"He'll be dead in moments."
Xander growled, sending a bone splitter into the memory of Tom Riddle. The spell phased through him easily, leaving the memory to smirk.
"Help me up." Harry said.
"Mate, you need to stay down."
"I said help me UP."
Ron swallowed, but nodded, helping Harry up. Xander grimaced when he saw the tooth still jabbed through Harry's arm, broken off from the snake itself. The redhead helped his friend out from the mess of dead snake, Harry pale as a ghost as he glared at the memory of Tom Riddle.
"You won't win. I won't let you." He gasped out.
"Big words from a child only moments from death, boy."
Harry cast around and found what he was seeking. With a surge of strength he broke from Ron's grip and stumbled to the ground, grabbing the diary from where it lay beside Ginny Weasley.
"What are you doing!?"
Harry jerked the tooth from his arm, smiling a death's head grin at Tom, and jabbed it into the diary with the last of his strength. The Diary began to smoke instantly, and Tom began to scream. In seconds there was black smoke rising from the ruined book, and a spirit like form erupted from it, howling in pain, and then vanished.
Harry collapsed back as the others stared in shock.
"Whoa." Xander muttered.
There was silence for a long moment, then the phoenix song erupted again as Fawkes circled around and landed by Harry. The bird looked the boy up and down for a long moment, the tilted its head sideways and shed a single tear into the wound.
"It's... it's closing up." Ron said, leaning over Harry's arm.
Xander slumped down on the coil of deadly serpent and let out a sigh. "Yeah. You know what, next year, leave me out of you adventures. K?"
Ron stared at him, gaping for a long moment, but Xander just ignored him as he thumped the side of the snake idly.
"Oh yeah, and just FYI," He said, "I'm staking a claim here and now, I'm getting me a pair of snakeskin boots out of this deal at the very LEAST."