The thumping of his heart had refused to stop, despite having been lying on the floor for an hour. He knew it had nothing to do with exerting himself; he ran fast but that's a usual thing for him.
So why was he being tormented so? It wasn't even a steady thumping, but irregular and weird. Sometimes it skipped a beat for no reason.
Was he sick?
He hoped not.
He had only been away a short time but it was time he wouldn't get back. He had jobs to do, and he'd be damned if he didn't finish them, in more ways than one. He jumped up from the floor, soundlessly, and stretched his arms above his head. He supposed he better get himself something good to eat.
Prison food was never his favourite meal.

...

If he was honest, then he would say fast food joints were not fast in the least. And he was honest, and was very nearly ready to say this to the poor teen who served him, when he felt the presence of someone enter the restaurant. He didn't see them, or hear them, but feel them. As if the air pressure shifted from the mere existence of this person. Or, in this case, cyborg.
Sonic felt himself stiffen involuntarily as he took his bag and, his shoulders drawn up to his ears, quickly dashed outside, eyes glued to the floor. He made it outside faster than he had intended, and hid himself behind a potted bush out the front. He didn't bother with making sure he was completely concealed, he was assuming the darkness of the night was enough to hide him. With his eyes now glued to the front door of the fast food place, he slowly opened his bag of food, pulling out one fry at a time and munching on them slowly. He was so focused on the door, he didn't notice the people around him staring. And he definitely didn't notice when one man came up close to him, until he was tapped on the shoulder.
Faster than anyone could see, Sonic had his sword out, ready to kill the one who disturbed him, but he was stopped. The one man who clearly saw through his ever move every time stood before him.
"Saitama."
"What are you doing?"
Not wanting to lose yet another sword, Sonic sheathed it quickly, as the pedestrians around them quickly turned away, or ran. It's not that Sonic didn't notice them running. He just chose not to care in this particular moment.
"What does it look like I'm doing? I'm eating." Sonic huffed, pulling out another fry and shoving it in his mouth to prove a point. The egg headed man gave him a strange look.
"On the ground behind a bush?"
Sonic said nothing in return, merely ate his fries, his face set in a stubborn pout. Saitama shrugged, then stepped past him, toward the fast food entrance.
"Well, enjoy your food, Panic." he said with a half wave. Sonic ground his teeth together and clenched his free fist.
"It's Sonic!" He shouted, startling the few people around him. Saitama probably heard him, but he doubted the man would acknowledge his name.
He huffed and shoved some more fries in his mouth, turning on his heel and moving to find a nicer place to sit. He settled with the cafe across the street, which had their tables out even though no one was around. It was late, and he was pretty sure he scared away a lot of people.
It's funny how frightened people get at the slightest glint of a weapon.
He had just about finished his meal, which consisted of the last few fries, and a burger, when he head someone walking towards him. He casually placed a hand on the hilt of his sword, always ready.
"It won't help you much." A voice said to him, and he felt his body tense up. His heart started up that weird thumping again, irregular and oddly painful. He turned. The cyborg that always followed Saitama around like a lost puppy was a mere few meters away, and coming closer. Sonic's heart continued with the horrid thumping, and he was certain it was loud enough that the cyborg would pick up on it.
"W-what do you want?" Smooth, Sonic, he thought to himself. Not only is he gonna hear your heart, but now he's gonna think you're scared or something.
If it wouldn't look like he was running away from Genos, he would run away in an irregular heartbeat. Genos stopped moving, now standing just a few steps away.
"Sensei said you were spying-"
"I wasn't spying!"
"-on me."
"I wasn't spying on you! If you really must know, the manger of this joint is destined to die."
Well, it wasn't a lie. The manager was destined to die. But not by Sonics hand. He turned down the job due to lack of funds.
Genos' permanent serious frown grew more serious.
"You shouldn't kill people."
Sonic snorted.
"It's what I do. Like how you play the Hero, I'm the big bad villain. Besides, apparently he molested some kid or something. Does that make it any better for you, Demon Cyborg?" he spat out the words 'Demon Cyborg' as if they were too dirty for his already impure tongue.
Genos' face didn't change, nor did he respond.
Sonic found himself suddenly wondering about if the cyborgs face ever changed. Was he ever anything but serious? What other expressions could he make? He frowned at himself.
Why the fuck was he thinking so deeply about the cyborgs face!?
"You should leave the job for the police or other heroes. They will apprehend the criminal and bring him to jail."
Sonic rolled his eyes.
"I was at jail, sweetheart. Got out recently, actually. It's not what you think it is. He won't get what he deserves at jail." Sonic clenched his fist and stood up from his seat. His heart had refused to stop with the infernal thumping, and he was beginning to feel somewhat tired. "But that's besides the fact. You messed up my job, which means I have to come back a different day. So thanks a lot."
Genos cast his glance at the table Sonic was sitting at, the scrunched up wrappers and bag left forgotten.
"Are you going to pick that up?" he asked. Normally, Sonic would just sneer and leave without caring for his litter. He was a very busy man. But for some completely irrational reason that he couldn't figure out, his arm reached out by itself, and picked up the trash. Not only that, but he also walked over to the trash can and threw his waste out. He turned his hand around, palm up, and stared at it, unbelieving. What the fuck just happened. He turned back to Genos, who's expression didn't change. He then made a tch noise, and turned on his heel. Before he could take his first steps, Genos spoke up.
"You should see a doctor about your heart. That is not a normal beating pattern."
Sonic's face flushed red, and he was infinitely glad he had already turned away.
"Pshh, whatever." He replied, not bothering to wave as he ran himself home.
Left back where he was standing, Genos watched the ninja leave until he heard Saitama call for him.
"Coming, sensei."