BtVS by Whedon and Mutant Enemy. Star Trek:TNG by Roddenberry and Paramount. DC by the parent company and their many artists/writers.
Through a dark alley stalked Edgar the vampire. He wasn't exactly hiding from the chaos in the streets as much as trying to occupy what seemed to be a safe place for easy prey to run to. When a supernaturally strong hand grabbed his neck from behind and lifted him off the ground, he realized he wasn't the only one to have the same idea...
"You can't do this to me," Edgar choked out. "I'm a follower of Spike the Bloody and Drusilla the Mad! They're the top dogs in this town." For all I know, he thought uncomfortably, it's one of them behind me. I'm better off playing it safe.
"Yes, I know," came a man's voice. "I've seen your camera work. You need to round up all those loyal to your masters and have them be on hand."
When Edgar was unceremoniously dropped to the ground, he landed awkwardly on his hands and knees. "That's not going to be easy," he said as he stood, brushing himself off. "It'll take some persuading. Especially if Spike and Dru say any different."
"That's alright. It's for their own good," came the voice, tinged with dark humor. "I'll even come along to force some sense into each demon's head. Because, at least for tonight, the greatest power in Sunnydale..." There was the sound of cracking knuckles. "Is me."
When Buffy-Ghost and Soldier-Xander rounded a corner they found themselves face to face with two people in Starfleet uniforms.
"Well," said Riker as he eyed the young woman's clothes and the young man's archaic weapon. "You two seem to be the sanest out of everyone we've seen tonight."
"I wouldn't go that far," Xander snarked as he waved his arm through 'Buffy.'
"Fascinating," said Beverly as she pulled out her tricorder and aimed it at the specter. "She's freefloating realized potential without a physical anchor. Or, rather, she's a mobile echo being projected like a remote-controlled hologram. He seems to be solid, with similar readings as us... And I'm sorry. This is Commander William Riker and I am Doctor Beverly Crusher."
"Right," said 'Buffy.' "I'm Slayer Buffy Summers, this is Xander Harris, although he doesn't know who he is right now. Have you guys seen Deanna Troi tonight?"
"Well," said Riker. "Good to know she's here." He hoped that at least she had arrived in her uniform. "Although it raises the question as to why we arrived in different places. No, this is the first I've heard."
Xander shrugged. "What she's saying and, from the fact that you guys are fictional characters I'm inclined to believe her, is that we're all victims of enchanted costumes that override memories. I'm either her friend in a soldier costume or, considering you guys look exactly like your actors, I'm someone who dressed as her friend in a soldier costume."
"Probably not the latter," Buffy said as she mimed patting him on the shoulder. "You, er, Xander, doesn't exactly have a fan club. Anyway, we're headed to my house in hope of stragglers and weapons, then on to a defensible centrally located place with research materials."
Riker exchanged a glance with Beverly. "Sounds reasonable," he said carefully. "If we're in a holodeck there could easily be trap programs disguised as objects that activate on touch. I'm assuming there's a player somewhere, if we're part of the simulation, rather than this being a show for our benefit."
"So," he said, turning to Buffy. "We'll be happy to follow you around. For now, at least. What's our show called? Enterprise?"
As they started walking, Buffy explained about Star Trek, with Xander throwing in a few comments here and there about Riker and Troi's counterparts' work in the Gargoyles animated series.
"Hmm..." An evil smirk spread across Riker's face. "Dr. Crusher, I believe that while we're here we need to track down the work of this 'Sirtis'. It's quite a shame that Worf was the only one to agree to wear the clothes of his dimensional counterparts for his bet, or we could see a 'Demona' serving her shift on the bridge of the Enterprise..."
Xander cracked up. "No, don't worry." He said, wiping his eyes after a while. "He's in there too. I can also maybe see him as Lord Nebula... But there's no way you're getting Worf to dress up as I.M. Weasel... Wait, do you hear that?"
Riker opened his mouth to respond, when he heard a woman screaming in time with loud growls. His eyes flicked over to Buffy.
Buffy sighed and pointed. "Three streets down? Palm trees, white trim. 1630 Revello."
Riker nodded. "Xander, with me. You two secure the base."
As the two men ran off, Buffy muttered something about 'not splitting the party in horror movies' before turning to face her home.
"Buffy, watch out!"
Buffy swiveled to face Beverly, only to get a faceful of child-sized bee. It, of course, passed right through her to collide with a small fence. While Buffy was left brushing at her face making sputtering sounds and the bee was buzzing angrily as it tried to pick itself up off the sidewalk, the fence was consumed in flowery vines originating from the point of impact. Not wanting to see what the bee could do to living material, Beverly fired enough stun blasts to chase the creature up and over the row of houses.
Sighing, she returned the phaser to its holster. "Let's get off the street."
A short sprint later, Buffy was talking Beverly through finding the spare key. When the door was open, Beverly attempted to enter, only to find her path blocked by an invisible barrier. Buffy 'brushed' past her, oblivious to the Starfleet officer's confusion.
"Well, what are you waiting for," Buffy asked as she checked the house for costumed infiltrators. "Come in, I can't turn on the light by myself..."
Her words trailed off in horror as she turned to find Beverly pressing her palms against empty space, in the same way she'd seen vampires 'mime' while attempting to enter places they weren't invited...