I've been wanting to do a Batman crossover for some time. I originally intended this one to be one with Batman: Arkham Asylum (I love those games), but I think it'll work better as a crossover with the comics, albeit with only loose ties to the comics' continuity. Seriously, that's Brobdingnagian shit right there, the continuity of DC Comics. Even more so than the Whoniverse, and that's saying something.

I'm not the first person by any means to make Poison Ivy Harry's mother, adoptive or otherwise. whitetigerwolf has certainly beaten me to having Lily Evans as Ivy in their one-shot Interview. But this, I think, is the first substantial story to have Lily as Poison Ivy. Assuming it gets decanted from The Cauldron, anyway...

VERDANT MAGIC

CHAPTER 1:

REUNIONS

Madam Dolores Umbridge, Senior Undersecretary to the Minister of Magic of Britain, was an odious, nasty, cruel, and all-round immoral human being. In short, she was a bitch who looked like a poorly-transfigured toad turned into a woman, and stuffed into a cardigan dyed an eye-burning pink. But one thing she wasn't was stupid. Not wholly, anyway. To become the power behind the Minister of Magic, one had to be intelligent and savvy enough to navigate the brutal and Byzantine politics of Magical Britain.

Of course, of all her actions, this had to be a masterstroke. In her efforts to help discredit Dumbledore and his pawn, Harry Potter, she had considered many things. As the smear campaign against them mounted in The Daily Prophet, Umbridge had considered sending Dementors after Harry. Now that would be good. Either Harry ended up a soulless husk…or he would be forced to use magic to repel them, and thus get in trouble with the Ministry for repeated use of magic in front of Muggles.

But Umbridge had now found something else. Something that would prove to be, if anything, a more devastating weapon. One that, at the very least, would wipe out a lot of support for Dumbledore in one fell swoop, and even turn Harry into, if not an ally of Umbridge and Fudge, then at least Dumbledore's enemy.

Which was why she had gone to Gotham City, and spent time amongst the frankly filthy Muggles there. Until she found the person she was looking for. It had been an arduous few hours, talking to that person and undoing the spells which had infested them. When that person had learned what had been done to them, and by whom, well, they were angry.

Umbridge also knew Harry Potter's home address, and had supplied it to that person. After all, if anyone deserved to know that address, it was that person. Even if they were a known criminal. But then again, what could you expect from a Muggleborn?

"But Red, this is so boring," whined a voice. The woman the voice belonged to was beautiful, with long blonde hair framing a pretty, 'girl next door' face. She was wearing jeans, and a T-shirt with the Mona Lisa, with a moustache and beard on it, and the caption LHOOQ below it, a rather highbrow joke for the woman(1). "Seriously, it's even worse than home. At least you've got graffiti livening the place up."

The other woman rolled her green eyes. Her face, framed by masses of red hair, was haughty and regal, her clothes a little more elegant than her companion, with a green blouse and black jacket and trousers, concealing a body many a woman would kill to have. A wide-brimmed hat completed the ensemble. When she spoke, her voice was a sultry purr, even when it wasn't actively trying to seduce. It also held a certain amount of weariness and anger. "Harleen, we are not staying here longer than necessary. Especially as that old wether(2) may have the house watched. We need to be in and out before they can react. And I'm not sure whether the Disillusionment Charm will work, especially if Moody's watching, though he would have come forward by now if he was."

"Can I still beat them up a little, Red? I mean, given what you told me, they probably deserve it."

"If we have time, and I see enough, yes." They walked through the rather bland, dreary street of Privet Drive, Little Whinging, Surrey, where the houses were almost like clones formed in a vat. As they approached Number 4, the woman called 'Red' flinched and stopped, before scowling. "That old wether has put up wards here to influence the inhabitants."

"Well, 'snot like it's gonna be a problem, Red, once we take the kid outta here," Harleen said with a shrug.

"True. Of course, the wards geared toward the Dursleys are designed to enhance natural hatred and aggression, while towards…" 'Red' stopped for a moment, overcome by emotion. Eventually, she said, "They're suppressing magical ability, ability in general, intelligence, acuity…as well as instilling loyalty. I'd be impressed if I weren't so angry. It's a very difficult and intricate bit of spellwork." She then approached the door, and rapped imperiously on it.

Eventually, the door was opened by a man who appeared to be a human walrus, obese, moustached, and ill-tempered. "Who are you?" he demanded belligerently.

"Vernon…time hasn't been kind to you at all, has it?" 'Red' purred. "It's been kinder to me, though I cannot say it is due to clean living."

Vernon blinked, before his eyes widened. "It can't be you. You died with that other freak!" But as he tried to slam the door shut, 'Red' held it open, even against the strength of Vernon Dursley. Then, after a while, Vernon's face went slack, his expression becoming blank.

'Red' and Harleen walked right in. The red-haired woman seemed to sniff the air, before she honed in on a cupboard underneath the stairs. She opened it, and then scowled. "What the hell are you doing here?!" screeched an unwelcome voice.

'Red' turned to stare at a rather long-necked, horse-faced woman, who stared at her in shock. "No…you're dead…"

'Red' rushed forward, and grabbed the woman by the throat. "You'll wish I had, dearest Petunia. I could smell his blood in that cupboard. And while that old goat's wards would have affected you, I didn't think that you would have done that unless you wanted to! I would have looked after Dudley if you had died."

"We…never wanted…the freak…" Petunia choked out.

'Red's eyes narrowed, and she shoved Petunia to the floor, gesturing. From out of nowhere, ropes conjured themselves around the woman's body. "Where is he? Tell me, and I will leave this house, with him."

"…Guest bedroom…"

"Thank you, Petunia. And goodbye. Harleen? Put the clown's toxin next to her. He's good for something, at least."

"Sure thing, Red." Harleen grinned, and placed a small cylinder with the distinctive emblem of a psychotic, grinning clown on it, in the centre of a spiral made of alternating arcs of sickly yellow and purple. "What time?" she asked, her fingers poised above a timer.

"Three minutes. Vernon, close the door and come here," 'Red' called out.

As Vernon approached, and 'Red' also incarcerated him in ropes, Petunia said, "For pity's sake, I have a child!"

"So have I, and look how you treated him," 'Red' scowled in contempt. "Goodbye, Petunia."

"For pity's sake, Lily!"

"Lily Evans died long ago," 'Red' said coldly to the woman she once considered a sister. "And what little pity I had for you died when I smelt that blood in the cupboard." And with that, she began walking up the stairs, Harleen in tow, ignoring the protests of the woman tied up behind her.

"Y'know, this magic thing is pretty useful, Red," Harleen said. "You should use it more often."

"I only regained it when that odious woman broke the remaining binds on my power," 'Red' said. "As much as I hate helping the Ministry's little smear campaign against my son, it is past time I came back into his life. And in any case, this will give that old goat a declaration of war." Reaching the door, she opened it, to find her son sitting, reading, only for him to look up.

For the woman known as 'Red', it was a startling moment. He looked so much like the man she had been tricked into becoming infatuated with. And yet, there were different qualities in his face, beyond the scar and the green eyes, so much like her own. Remembering she was on the clock, she said, "Pack your bags. We're leaving."

"Who are you? What are you…" He blinked as he seemed to recognise her. "No, it can't be, it's a trick!"

Dammit, 'Red' thought to herself, before sending a sleeping spell his way, hitting him before he could react. The snowy owl in a cage barked in fright. 'Red' began checking, getting a trunk, and nodding, before pulling out what she could manage from the cupboard. Putting the cage and trunk, along with what she had managed to pull out, she then plucked a piece of paper from her jacket, put it onto the things, and had Harleen put her hand onto it, while 'Red' put the boy's hand onto it. As laughter sounded from the gas bomb downstairs, 'Red' said "Demeter." The three people, one owl, and a lot of luggage vanished, while the two people currently in the house died laughing, literally, their faces becoming pale and with rictuses on them. Dudley Dursley, who was out taking boxing lessons, came back to find his parents dead, and the freak missing. And he didn't know where his cousin had gone…

"Y'know, I hate bein' out in civvies," Harley Quinn complained as she donned her habitual, figure-hugging red and black suit, reminiscent of a jester. They were now back at one of Ivy's hideouts, at an old, abandoned garden centre. "It's so much more fun bein' in costume. It's like playing dress-up every day. I guess that's one of the attractions for B-Man. I mean, why else would he dress up like a frickin' bat?"

The voice of her co-conspirator, frequent lover, and probably only actual reliable friend, came out of the wardrobe where she was dressing, wearily. "The Batman is disturbed, Harley. Madness is a debatable thing, especially where Gotham is concerned, but one thing we can agree on is that disturbed individuals are on both sides of the law."

"I never heard you talkin' like that before, Ivy," Harley said. "Ever since that toad woman came 'round, you've been actin' a bit weird. I mean, beyond havin' a kid I never knew about, and bein' a witch like Zatanna, and having a British accent all of a sudden."

"At least the Batman is, for all his sneaking around, honest about his purposes. He'd fit right into Gryffindor…or Slytherin or Ravenclaw. Or Hufflepuff. To get where he is, he'd need a lot of hard work and tenacity."

"Yeah, I dunno half the stuff you're talkin' about, Red."

"Don't worry, Harley," her lover said, walking out of the wardrobe. Her skin, originally pale, was now the light green of a sapling. She was now dressed in what could be described as a one-piece swimsuit, seemingly made of leaves. "The upshot is, I have a new perspective on things. My mission hasn't changed, just something of the way I go about it. And the Batman will still seek to incarcerate me for my crimes past and future. And, of course, you're still mine."

"Aw, you're so sweet, Ivy," Harley said, smiling at Poison Ivy, one of the most infamous criminals to operate in Gotham. As was herself, but it was not unusual for the so-called supervillains, as the hysterical media dubbed them, to congregate. And ever since a fateful encounter five years ago, the two were lovers as well, albeit with a somewhat fractious relationship, partly because of Harley Quinn's obsession with the infamous psychopath known only as the Joker.

Still, at least the insane 'Clown Prince of Crime' had been good for something, Ivy reflected. Harley happened to have a gas bomb with his infamous Joker venom, a substance that provoked a fatal gelastic seizure, or, in layman's terms, they laughed themselves to death, the gaseous toxin pulling their faces into a grotesque smile like the Joker. Harley and Ivy were immune, Harley because of repeated exposure to non-fatal amounts of the toxin (as well as Ivy giving her a means of resisting poisons), and Ivy was immune to poisons in general. But to kill the Dursleys in such a way…well, it was immensely satisfying, and it might divert a little attention: Ivy's animosity towards the Joker was well-known.

Poison Ivy sighed quietly to herself. "Come on, Harley. I think I'll need you there with me. This is probably the hardest thing I've done since Woodrue experimented on me. That fool thought he was modifying me, when in truth, he was setting part of me free. Just not all of me…"

There he was…her son, lying there in the bed of her makeshift infirmary. Harry Potter, the Boy Who Lived (and if someone other than Dumbledore had thought up that little sobriquet, she was going to feed them to one of her plants). The one she had been forced to have with that bullying son of a bitch James Potter, thanks to Amortentia, and a bunch of other potions and spells. The one she was set up to be a brood mare for by Dumbledore. But while she could see James Potter's features, she also couldn't see him as anything other than her son, all grown up. A son whom she had been forced to forget. She wasn't going to hold the sins of the father against him, and despite the lies The Daily Prophet printed, she was almost certain he was nothing like his father in character.

Gently, Poison Ivy waved a hand, and murmured, "Finite." Her son's eyes flickered open. When he saw her, and Harley, he blinked.

"Okay…I'm going crazy."

"Kid, it helps in this city," Harley said, probably not helping the matter, though her tone was gentle.

"Who are you?" the teenager demanded. "You can't be my mother, she's dead, and…hang on, aren't you Poison Ivy? And Harley Quinn?"

"That we are," Harley said.

"I don't know how I can't have seen it. I have that photo album from Hagrid," the teenager was muttering.

"That's because there's a certain man who has a lot to answer for," Poison Ivy said. "Magic was involved in blinding my eyes to the truth…and everyone else's. In Gotham, I am known as Pamela Isley, aka Poison Ivy. But…I was born Lily Evans. Harry, I know this is hard to believe, but I am your mother."

CHAPTER 1 ANNOTATIONS:

So, here you have it. Poison Ivy is really Lily Evans. Harry's just been chucked in the deep end, and the Dursleys (well, two of them at least) have suffered a justifiable demise. Seriously, Joker gas is too good for them.

1. LHOOQ is a famous parody of the Mona Lisa by Marcel Duchamp, which has the Mona Lisa with a moustache and a beard. Spoken out loud in French, the initials LHOOQ sound like the French words 'Elle a chaud a cul', literally meaning 'She is hot in the arse', but less figuratively meaning 'She's randy'. I reckon this sort of thing would be right up Harley Quinn's alley, given the Joker's propensity for vandalising works of art and bad jokes.

2. As mentioned in previous fanfics, 'wether' is a term for a castrated goat. I found it while writing Fall to Zenith, and found it an excellent insult for a bashable Dumbledore, or else being used by his enemies in stories of mine where he isn't being bashed.