Grief is like energy, Tony decides.
—
After the snap Tony was left in the back of a spaceship hurtling towards earth with only a blue skinned metal alien for company.
"We need you alive Stark," the alien had said after he refused to leave Titan, his fingers coated in dust. "Your life came at an expensive cost. You are not dying here."
"I know," Tony croaked.
There was always the potential for grief. Just like potential energy grows as an object speeds away from the surface of the earth. Just like a spaceship chased away from an orange grave.
—
Tony’s theory is affirmed when they get back, weeks later, having been saved by a glowing, red, blue, and gold lady.
He stumbled off the ship with more speed than he thought he had, his vision tunneled into a small dot.
Steve came running up to him. He knew they were fighting, that he was still angry with him for his whole running away stunt, for a million different reasons... but in the face of everything else, that hurt was inconsequential.
“I lost the kid.” Tony croaked. Steve holding his bicep, Pepper running towards him, he wobbled on his feet. Yeah, energy he thinks, before the whole world goes dark.
He can still feel the grit of dust on his palms.
—
The first week back is hell.
When Tony woke up on Earth for the first time in over a month, it took several seconds for him to remember what had happened. When he did, he could barely breathe.
He sat up abruptly, hand pressing down on his chest, black spots erupting in his line of sight. He gasped shakily, pressed with his hand, exhaled. Pepper and Rhodey were there the next moment, gentle hands on his shoulder and cheek, the cool brush of hair on his neck.
His breath rattled in his chest for another 15 minutes. After it stops, he chokes on his own voice, trips over words until he’s back to gasping. Pepper and Rhodey sit with him for a long time before he finally drifts off.
—
Tony doesn’t know if he’s ever felt something so enormous before. He remembers the weeks, months, after his parents; Jarvis. He thinks he should have been more prepared for this moment. This weight.
The more mass a thing has, the greater force it exerts under the same conditions of acceleration. Newton’s Second Law.
Tony knows this. He just never thought he’d have to reckon with it the same way he does now.
At the end of a three day work binge in the lab, he brings up old baby monitor footage. Tony watches and watches and watches. He doesn’t think he’d ever noticed the slight inflection in Peter’s voice when he talked to his AI’s. Nor the precise angle that Peter most commonly ended a swing at. FRIDAY asks if he wants her to keep playing the footage a couple hours in. Tony jolts, snaps at her to turn it off and put the footage on a locked server.
His body is heavy, so he decides to sleep on the couch in the lab rather than make the trek to his room. He falls asleep with equations in his head, calculating the force it would’ve taken to get Thano’s gauntlet fully free from his hand in time.
—
Three months after Thanos and dust and Peter-
Three months after The Snap, Tony and May go out to lunch.
At first they’re quiet. Picking at their Thai and watching the cleanup crews through the windows.
In the end, it’s May who starts it. She says in a small voice how proud she is of Peter, how brave and kind he was.
“I pretty much lost it when I saw him in that suit the first time,” she admits tearfully, “I was angry, but I was also just scared.” She wipes a hand across her face. Tony can only nod.
“He was so... so...”
“Stubborn?” Tony prompts. May nods, let’s out a wet laugh.
“Yeah, that.” She pauses for a moment, tries to collect herself. When she speaks next it’s almost a whisper. “He took everything on himself. Why did he do that.”
“When you can do the things I can do, and then the bad things happen, they happen because of you.” Tony recites, monotone.
May stifles a sob. “God, sometimes I wish he’d never been bitten. Is that selfish? I know he’s helped so many people and I know he loves it I just... sometimes I just...”
“I know what you mean. Though Pepper might say otherwise.” Tony says and May laughs.
When they leave, they share a long hug and Tony promises to visit soon. He feels guilty admitting it to himself, as if he’s betraying Peter’s memory, but an energy that’s been static in his chest for too long expunges itself, and he smiles at May before she turns.
—
Nine months after The Snap, Tony sees his kid again. The sky is overcast, the ground torn up by Thanos’ monsters from hell, but to Tony, it’s the most beautiful the earth has looked in a long time.
He watches Steve drop the guantlet out of the corner of his eye, sees others reuniting with their loved ones across the Wakandan plain.
He can’t move. He’s out of the suit, and for all intents and purposes, he’s physically okay. But it’s like all his kinetic energy has been stolen from him. Like when the grief rushed out of his body upon seeing Peter, it took with it everything that had kept him functioning.
In the end, Peter’s the one who comes to him.
“Mr. Stark!” he calls, mask in hand, grinning like he hadn’t just been dead for most of the year. As soon as he’s within arms reach, Tony pulls him into a hug.
“Kid, Peter, kid.” Tony whispers against his shoulder, clutching at his back.
“Mr. Stark, I’m okay.” Peter says, but he doesn’t let go of Tony. They stand there for a long while, as the clouds break overhead, and the sun spills over the grass.