BtVS by Whedon and Mutant Enemy. DC by the parent company and its many artists/writers.
For reviewer BarbarossaRotbart who liked my 'Forgotten Life' concept, but wanted to see it as a straight Buffy/DC cross. Guess I'll start the story with an event a few months earlier to give me some writing room...
Prologue: Graduation Day
Lois Lane was sitting at her desk in the offices of the Daily Planet when the phone rang. After few minutes spent verifying that the caller was a high ranking member of the British Consulate in Los Angeles and that the next person had governmental backing as well, although of the more shadowy sort, the phone was passed to an older man with a refined accent and warm, controlled tones.
At the end of the call, Lois returned the phone to its hook, spun around in her chair with her notes held firmly in her hand and called to her husband across the room. Clark ambled over carefully. He'd started paying attention part-way through the conversation, enough key words having filtered their way through his super-hearing, and he was curious about what he'd missed.
Lois shrugged and spread her arms. "Looks like I've another message for Superman when he stops by. I'm glad I have a secretary who screens these calls or we'd be buried in them. This one's from a Doctor Rupert Giles who's employed by the British government as an alien hunter. Apparently there's a Southern California town that was founded in a crater called the 'Mouth of Hell' by the original settlers, because of weird events associated with the crashed spaceship at its center. The first on the scene who decided to stick around was a man called Richard Wilkins. He's allegedly still alive and still Mayor even though he founded the town a century ago today."
Clark tilted his head and looked at her curiously. "Think he's using advanced tech, he's bonded with an alien symbiont, or was replaced by one completely? I know the anti-aging treatments Waynetech's putting out as part of their trade deal with Atlantis have had some pretty spectacular results so far but, for a baseline human, that seems pretty excessive."
"No, it gets even better. Turns out that he's been spawning shades for years that go out into the town at night and suck out life force for him to consume at his leisure while he's safe inside a skintight biomechanical forcefield. Dr. Giles called because Mayor Wilkins caught wind of his attempts to translate old records and came to gloat and destroy hospital property. Apparently whatever species Wilkins is emulating was able to 'ascend' to a greater 'king' form as part of it's life-cycle once it spent exactly a hundred of the local years ruling those around it."
"Ouch," Clark winced. "How long do we have until this supposed clock runs out? Is he suddenly going to meld everyone around him into a single hive mind, or is it one of those where he gets really big?"
"Shortly after three PM Pacific time, so we have hours to pass this on to Big Red. He's apparently going to get huge, grow much bigger than his arms and legs, and start eating everyone around him."
"Doesn't sound like a very stable form of government," Clark said, adjusting his glasses. "Especially if it's irreversible they'd have to redesign, well, everything... I guess the best we can expect Superman to do is to hang around stealthily and swoop in if anything seems fishy."
"Definitely. The last thing we want to get passed around is that Superman's gullible enough he can be tricked into attending anyone's highschool graduation ceremony."
Clark blinked. "Seriously?" At Lois' nod, he said some kind parting words and walked off to his desk.
Pulling out a sheet of paper, he began taking down some shorthand notes. If Clark was going to be abducting the keynote speaker in the middle of the ceremony, then he definitely wanted to be prepared to come back and finish the speech himself, assuming the school was still in one piece.
Clark, as Superman disguised in a bulky blue janitor's uniform, arrived at Sunnydale High rather early.
A quick scan revealed an unarmed set of explosives in the library. Wincing, he upgraded the size of the Mayor's king-form a few stages if they expected to need that much to take him out, assuming the call for help was legitimate. After reassuring himself he could disarm and move the explosives with a moment's notice, Clark moved on to examine the students.
The majority of them had weapons hidden under their robes, but these were crossbows and bats and other things best used against human-sized enemies. Sighing, Clark began to search for the Mayor's minions. This used up most of his available time until a chance glance downward with his x-ray vision revealed figures hiding in the sewers, presumably the life-sucking shades geared up for a final feast.
After speeding around, welding the main exits from the sewer shut with his heat vision, he dove in to clean house. He emerged a few minutes later, battered and bleeding. The creatures in mostly human form had proved no match for him in confined quarters, but their teeth had somehow managed to break his skin and leave deep grooves in several places. The few able to reach him at a time simply weren't strong enough to press that small advantage, but he really had no desire to see what they could've done under a different battleground...
Xander's face alternated between a wide grin and a worried frown as he sat in the back of the graduation ceremony. He'd taken the time to check on something and what he'd found meant his plan had either worked or things had taken a horrible turn...
When the sun suddenly disappeared from the sky and the Mayor had choked out what would probably be his final words as a human, the Mayor's skin began to bulge and distort and grow-
Which was when there was a brilliant blur and the Mayor was gone, with the sound of something huge slamming into earth very far away. As everyone shed their robes and prepared weapons for the expected onslaught, Xander walked out into the street and shaded his eyes for a better view. "Ouch," he winced. "There goes Kingman's Bluff. Did anyone know there was a temple buried under there?"
He watched, his gaze steady, until a hand landed firmly on his shoulder.
"Well, my boy," Giles said warmly. "Seems you were right. Couching everything in science fiction terms was the best way to seek help without tipping the Council's hand."
"Thanks." Xander grinned widely and returned to watching, just in time for a large blast of fire and smoke. "Ooh," he said, nodding appreciatively. "That's where my explosives went..."
"Ooh, my head," boomed the transformed and greatly enlarged Mayor as he lay on his 'back', staring up at the floating figure that had just finished securing his snake-like form in sufficiently advanced chains...
Clark counted himself lucky he'd moved Wilkins while he was still near human-size with enough force to put him at a disadvantage and keep him off-balance. The shades' teeth had put Clark on guard against Wilkins' chompers and, even with the first strike, the fight could've gone either way, with one deciding factor. Clark was pretty much immune to mundane explosions and Wilkins simply wasn't.
"If you can't breathe water," Clark said, his voice stern and even. "Now's the time to speak up. The King of Atlantis is about the only person I know with a jail properly equipped for you and I want to do everything I can to help this transfer go smoothly."
"You can't take me there," complained the Mayor, the free part of his tail thrashing weakly. "I'm an American citizen."
"Technically, I'm capturing an exotic animal that dangerously encroached on city property and donating it to a zoo in another country where I believe it will be cared for properly." Clark smirked. This was only one of several filing options, and probably not the likeliest, but he was enjoying the look on the Mayor's face. "With my team, the paperwork should go through easily. And, if it somehow doesn't, I'll pay the fine."