The scientists liked to listen to music while they worked. What kind of music, Rocket didn't know. But one day he woke up, his head oddly full with concepts and ideas that he'd never dreamt of understanding, and music was among those concepts. He'd never heard the original tunes. They were just in his head somehow.
He remembered them humming to themselves while they worked on him. He was always dazed and lightly drugged – just enough to keep him still and silent, but never enough to ease his pain. They always cut holes into him and always sewed him back up when they were done. But every time they did, another hole too deep to be reached grew wider and wider and never did get mended.
During skill tests, he caught himself humming those same tunes on more than one occasion. He hated himself for it. Somehow, it felt as if he were becoming one of them. As if he were contributing to his own pain by humming the songs they hummed. He knew it was never to be true. There was no way he'd ever be like them. He'd never become them, never belong like they did, never feel as if he actually had a place. Because they not only gave him the ability to walk, talk, fly, and create, but they also gave him a brain dense with stunning intelligence. He knew he was nothing more than an experiment, which meant that he was only meant to be temporary. When they were finished with him, they'd dump him somewhere and start anew.
Of course, since what they were doing had been illegal, they never got to start anew. All the other subjects before him had perished, and there would be no possibility of another like him.
Loneliness was painful at first. Over time, he learned to push it to the back of his mind and bury it under layers and layers of whatever he could get his hands on. His favorite became aggression. His second favorite became alcohol. When he didn't have his first choice, he went to his second, and when he didn't have the second, he always had his first.
And then sometimes, he had neither.
So he went to the third thing he could get his hands on – guns. He always chose to build them over buying them, except that when he built things and his fingers moved so nimbly over wires and coils and heavy metal he hummed those same damn songs and he ended up resorting to aggression all over again.
Eventually, that hatred for those songs was buried away as well, until even he couldn't feel his own self-loathing when he hummed the scientists' songs. It was always there, though. It was lingering just outside his field of vision, hovering over him like a demon just waiting for the moment to grab him by the neck and strangle him. The hole darkened and grew wider.
One day, Groot showed up. He eased his pain a little. The loneliness wasn't quite as strong, but it was still always there. At first, Groot was no more than another "favorite". But the more time they spent together, the more Rocket stopped thinking about him like that.
And then Peter Quill swaggered his way into his life. He brought with him Gamora, with her oh-so-responsible, stick-up-her-ass outlook on life, and Drax – a complete idiot.
They were all idiots. They stumbled their way through life, without a damn clue, about how cruel the galaxy really was. They had no idea how much pleasure the galaxy took in poking fun at small, forgotten, and misunderstood things like him. They'd never know; they belonged. They were born with their two legs and perfect speech and special hands and sentient minds.
But in the five days he'd spent with them, he found himself slowly realizing that he had been mistaken.
They all hurt. They'd all lost something. They were, as Peter had so elegantly put it before the battle on Xandar, losers.
He'd wanted to bristle at the remark, but couldn't find the anger to do it. Hearing someone who seemed to have it so easy calling himself and the other four surrounding him a bunch of losers did something to Rocket. The way they looked at him – so expectantly, as if he meant something to them and their mission – was enough to give him the strength to stand up.
The hole began to mend.
Rocket never understood just how mistaken he had been until the moment before Groot died. Up until that moment, he'd always thought that Groot wanted to stick around with him because Groot needed him. Rocket was so sure he'd always been able to handle himself, but he realized much too late that Groot stayed with Rocket because he needed Groot. Groot never understood the pain that Rocket went through, and he never would. But he understood Rocket's loneliness. He was alone, too, and he felt that same loneliness surround each of the others as well.
Groot pulled his friends into his cocoon that day to remind all of them that they were no longer alone. Like Groot, they'd never understand each other's pain, but they could understand each other's lonely place in the world.
Somehow, while they hurtled toward Xandar knowing full well that Groot was going to die for them, Rocket felt the hole deep inside mend a little more. And when he reached out for their hands, devastating purple energy frying every fiber in his body, the hole continued to grow smaller.
He used to be so afraid of death. Perhaps it was because of the thought that he'd die alone.
. . .
"Hm hm hm… have you ever felt the southern nights?"
Nimble hands worked over clanking metal and multicolored wires. The engine below him hummed as the Milano cruised through an endless sea of stars. Little, wooden feet tapped against the hard floor as Groot ran about the rooms, sometimes running into Rocket's tail. He could hear Drax and Gamora sparring in another room down the hall, and from the common room, Quill's mixtape played Rocket's favorite song. Something fell onto the floor, followed by a loud "oops" from the Terran, who'd obviously been dancing.
He'd never admit it, but Rocket enjoyed humming to Peter's music. Perhaps it was because he was no longer alone.