The backstory behind the robots was originally written by Loki's Minion Gurl, and presented in the fic "Don't Hand Me Things." Which, btw, is an awesome fic and you guys should totally read it. That having been said, on with the show!
Nikki chuckled as DUM-E tried to maneuver around a toolbox. "Where'd they come from, anyway?" Laserbeak, her new partner asked. "'I mean, I get that Stark built them, but they don't seem to stay in the garage, and they can't get up stairs."
"Tony's got a special elevator built for them that takes them from the garage to his lab upstairs," Nikki replied as she continued to work on a car. Laserbeak was silent for a moment before asking another question.
"...But they're just robots. Why does he accommodate them so much?"
"They're like his kids. He built them, he's fixed them countless times, and they've been around since way before he became Iron Man. DUM-E was actually one of his collage projects," she answered. "He loves 'em. And I have to say, they've grown on everyone, including me." At that, DUM-E chirped and toward them. "Yeah, we're talking about you, little buddy."
The robot rolled toward them, and Nikki chuckled fondly. "You comin' to see us?" When he got close enough, she gave him a pat.
"If he adores them so much, why give them such demeaning names?" Laserbeak asked. He seemed even more hesitant to ask this time than he did last time.
"Well, DUM-E's voice rec software didn't register any names or commands until Tony's dad showed up, and said that DUM-E wouldn't work and that he was a failure, and Tony got frustrated, called him 'Dummy,' and then he started responding. Butterfingers likes dropping stuff. Tony's fixed and upgraded software and mechanics, but it's not a glitch or fault. He's just fond of dropping stuff. U's ADHD, sometimes bounces off the walls - literally - and Tony could only ever get his attention by shouting 'Hey, you!" It just sorta stuck."
"Ah." Laserbeak looked at the robot, who waved to him. Laserbeak cast a glance to Nikki, who smiled. He looked back to the robot and waved.
Steve had searched the whole Tower for her, and in all honesty, he should've checked the garage first. After all, she was Miss Mechanic, and when she was feeling down, she'd go back to fixing cars because 'It's simple, it doesn't really change, and I won't screw it up.'
When he got down there, she was working on the Audi R8 Spyder. "Butterfingers, hand me that socket wrench, will ya?" The robot she called to was more than happy to do so. "Thanks." Butterfingers then picked up a regular wrench and started repeatedly dropping it - onto a blanket Nikki left lying around for some reason - and then picking it up. U was zipping around the garage, occasionally bumping into walls and tool carts (or whatever they were called; Nikki would know). DUM-E was playing with a fire extinguisher. Steve chuckled.
This got Nikki's attention. "Top of the mornin' to ya, Cap. What can I do for you?" she asked as she rolled out from under a car. The exposed parts of her skin were dotted with grease stains, as were her jeans. Her black t-shirt was concealing the grease stains on it.
"Heard you had a bad fight. I wanted to see if you were okay. Something must really be wrong with the car if you've got that much grease on you."
"Some of 'em are bruises, some of 'em are grease stains, some of 'em I don't know which is which, and sometimes I don't care," she answered nonchalantly. Steve frowned. "Oh, chin up, Cap. I'm fine. And Tony stuck me in charge of watching the Trio, so I have to be fine."
Butterfingers missed the blanket and dropped the wrench on the floor. The loud clang startled U, who bumped into DUM-E, who tipped over a little, which sent the fire extinguisher spray to the left, coating Steve. U started making a sound like chuckling while DUM-E beeped in alarm and Butterfingers looked completely oblivious to the situation. He was too busy being upset that Nikki was using his wrench.
Nikki laughed, and Steve was glad. He was laughing too - this was an absolutely ridiculous situation that he had no idea how to explain it to anyone else. Nikki handed the wrench back to Butterfingers and said "Try hitting the blanket next time, okay, buddy?" He 'nodded,' and Nikki went back to working on the undercarriage of the car. "Now you know why the blanket's there."
"Yep," Steve replied. "Oh, Laserbeak was looking for you. Said he wanted to know where the 'secret elevator' was." This got another chuckle from Nikki.
"Yeah, he doesn't believe me. Can you send him down?" she asked. "Thanks."
Laserbeak found her working on one of Stark's expensive and probably never used cars. The three robots were playing elsewhere. U was gliding around and smacking everything, DUM-E was giving one of the other cars a new paint job with the fire extinguisher, and Butterfingers was repeatedly dropping and picking up a wrench. Weirdos...
"Hey, Laser," she greeted. He'd given up on correcting her about his name almost a week ago. Humans were both strange and stubborn. Nicole Skylar was far from different. Well, in that aspect anyway. And she always seemed to know when he was coming! No matter how quiet he was, no matter how slick or secretive or silent, she always knew.
"I haven't found it," he cut to the chase. She rolled out, and for some reason, he almost twitched. Almost. "I think you were making it up." Not the best idea to challenge his superior, but he was still 'working on' losing the smug attitude.
She smiled and walked away. He - and Butterfingers, still holding the wrench for some reason - followed. She stopped by a panel in the wall near the south corner of the building. She pressed the button, and a part of the wall slid back to reveal the elevator. Nikki probably could've fit in it. Maybe Tony in a pinch. Someone like Steve or Thor, tall or broadly built people, wouldn't have managed to squeeze in. At least. not comfortably.
"Still don't believe me?" she asked, sounding almost as smug as he had a moment ago.
"Fine, yes, I believe you," he conceded.
"Good. And you can always ask me anything, Laser. I won't hold it against you," Nikki informed. He nodded. The sappy moment was broken by Butterfingers dropping the wrench.
"I see where he gets his name from now," Laserbeak remarked dryly as the robot picked the wrench up again. "Why does he keep doing that?"
"No clue. I figured, if I can't stop him, I'll just muffle the sound. Hence the blanket over by the car," she answered. She spotted U carrying the fire extinguisher and DUM-E chasing him. "Ah-ah-ah! Give it back, mister!" U immediately stopped, turned, and let DUM-E retrieve the extinguisher. "Thank you."
"They act like kids," Laserbeak remarked.
"They are like kids," Nikki replied.
"My kids," Tony cut in as he walked in. "And speaking of my kids, guys, we got work to do!" All three robots immediately stopped what they were doing, set their 'toys' down - well, Butterfingers handed the wrench to Nikki - and followed Tony to whatever part of the garage he was going.
"Yep, they are definitely his kids," Nikki said as she walked back toward the car.