He'd dismissed the idea of planting gas bombs at the party from the very beginning. They were certain to inspect the place beforehand. Knowing Batman's penchant for unearthing things he shouldn't, and knowing that the Bat seemed to enjoy nothing more than force-feeding him a faceful of his own fear gas, he wouldn't be surprised if all of them were delivered back to his lair to explode when he was least expecting it. Besides, what little fun he had in this life was generally had among the terror-filled hordes as he reveled in their screams...Yes, this party definitely required the personal touch.
The personal touch, however, was exponentially more complicated than simply hiding a few gas bombs under the floorboards. He needed a way to simultaneously gas hundreds of people. An army of masked henchmen bearing gas canisters would suffice, but it would also be far too suspicious, never mind the fact that he hated working with idiot henchmen who didn't know how to work a simple valve. The only answer he could think of was this: party favors. Everyone takes one, everyone gets gassed. It would mean round-the-clock work for two weeks to get them ready, but it would be worth it.
He'd been so busy that he hadn't remembered he needed a fake costume until three days before the party. Originally, his plan had been to wear his costume underneath another, shedding the top layer when the time had come to strike in order to reveal the full glaring glory of the Scarecrow amongst the partygoers. But the supply of costumes this late in the season was dwindling fast, and the number of full-masked costumes was almost zero. The handful of costume shops that he'd called had suggested things such as silly moose and fuzzy duck. If he hadn't been on such a tight schedule, he'd have dropped by and personally introduced them to his new toxin. Fuzzy duck, indeed!
He'd gotten his hands on a flyer advertising the party with hopes of coming up with some costume that walked the line between scary and non-threatening enough to let him in the door, preferably one with easy-to-find components. There were no costume suggestions, but the bottom half of the flyer was a list of costumes that were certainly not permitted. His eyebrows raised in astonishment as he saw every single costume idea he'd had laid out neatly in a row amongst the other forbidden regalia. Whoever had planned this party had tried to make certain that nothing even remotely scary got inside. Even the flying monkeys from the Wizard of Oz were there, sandwiched between Hannibal Lecter and Pennywise the Clown.
Seeing that, however, had given him a marvelous idea. He'd go to the party as...the Scarecrow of Oz! It was brilliant, particularly since it meant he wouldn't have to paw through racks of dimestore costumes alongside screaming children to find something acceptable. He had a large assortment of old costumes in storage in a lair across the city, after all, and it wouldn't be that hard to make a new mask that looked cheerful.
And now he stood in his chosen costume, adjusting the sleeves and re-tying the belt for the third time in as many minutes. This particular costume wasn't technically his. He'd stolen the clothes off of an actual scarecrow a few years ago when he'd needed a costume in a hurry. (There was something not quite right about facing off with the Batman in one's pajamas. Far better to wear actual clothes, even if they were dyed in sickeningly bright colors and sported cheerful patches in red and blue on the knees.) The whole outfit was at least six sizes too big for him and flapped off of his lean form like a priest's robe.
Still...he glanced back at the pile of discarded costumes. He wouldn't make it past the door in any of them. If the tattered and somewhat distinctive cut of them didn't tip someone off, the various bloodstains, burns and slashes certainly would. In fact, even his current costume was lightly scorched, but it wasn't noticeable unless you got close enough to it.
He settled his mask over his head. His mask, not the quickly-stitched beaming atrocity sitting on the sink, but the slit-eyed crumpled patchwork that was his trademark. The breath mask inside bounced gently off of his lips as he settled it in place. It was going to be stiflingly hot when he put the other mask on top of his own, but some things had to be endured. He had no intention of gassing himself at the party, after all, and attacking people while wearing an idiot grin certainly wasn't what he was known for. The happy mask would come off when the time was right.
He looked himself over again. Actually, he mused, the addition of his battered old mask lent a certain creepy something to the outfit, like a child's baby doll with a knowing smirk on its face.
He was wasting time. Resigned, he sighed and tugged the second mask down over his own, turning away from the mirror before he had to see himself in such a travesty. He knew his own mask wouldn't show through the one on top - he'd made the eye holes so small that he himself could barely see out of them, and the mouth had been sewn shut all the way across in a goofy smile - so there was no need to submit himself to the sight of this...this bizarro-land Scarecrow for even a moment.
He picked up his green backpack full of favors and headed for the door. It was party time.