clint/darcy/steve, batman
"Dude, Steve, you have to do it."
Steve rubbed the back of his neck and stared dubiously at the costume. "And, um, why exactly do I have to be Batman?"
Darcy looked over at Clint and rolled her eyes. "Seriously, what is wrong with this guy? It's not like we're making him go as Conan the Barbarian, all shirtless and oiled up..." She trailed off with a dreamy sigh.
Clint snapped his fingers in front of Darcy's face. "Hey, Darce, wake up!"
"Sorry, just had a mental image of Cap as Conan-era Arnold. You've definitely got the muscles. Anyway," she continued, "you have to be Batman, because Clint, with the circus background, is obviously Dick Grayson, aka Robin. And I do not have the requisite hunger for justice--"
"--or the figure," Clint butted in, leering at her chest."
"--or the figure," she admitted, "to pull off Bruce Wayne."
"And who are you going to be, then?" Steve asked.
"Your sexy arch-nemesis, Selina Kyle, aka Catwoman," she said with a wicked grin. "Gonna use your handcuffs on me, Batsy?"