Prompto had a habit of singing to himself, and most of the time he didn't even realize he was doing it. When he was happy or excited, when he was nervous, bored, or lost in thought. Sometimes he'd catch himself doing it and stop, only to catch himself right back at it a few moments later.
When they got into a fight and things went smoothly he'd sing a victory song, it didn't have any lyrics but it sounded like winning. At some point he'd started singing the same song when he pulled out his big gun too, because a big gun felt like winning.
In the car when flipping through pictures Ignis would sometimes chastise him for humming. Every single time he didn't even know he was doing it until he got called out. "Prompto, would you kindly stop." Ignis would say, followed by, "It wouldn't be so bad if you were humming along with the bloody radio."
When Prompto was nervous he'd sing as if distracting himself from it, like if he was making noise his nerves wouldn't bother him. He found that mostly happened in Hammerhead, or on the way there. He'd start thinking about Cindy and next thing he knew he was singing a wordless tune under his breath or humming some made up song. Sometimes he'd catch himself, other times it was Gladio not-so-gently reminding him to shut up.
The worst thing for everyone was the chocobo song, not that it bothered him, he never got tired of it. When they finally were off to see chocobos for the first time after leaving Insomnia he spent the whole day singing the song. 'I want to ride my chocobo all day.' It was so catchy, and whenever he thought about how he was finally going to get to see and ride a chocobo he'd just couldn't help himself.
The thing about it though, was that it stayed in his head forever. No matter what else they listened to in the car, or if anything else popped into his head, it was short lived and he'd always end up back at the chocobo song.
The Moogle Chocobo Carnival made it worse, with all the birds lined up for people to pet, the merchandise and people in costumes, not to mention the song playing everywhere he just had it permanently on loop in his head. He could swear it played in his dreams. It had become his default over the last few weeks.
Then there was everything that happened with the Empire in Altissia, Luna's death, Ignis's eyes, the fighting between Gladio and Noct. He just didn't have it in him, the music had stopped.
It was as if that little part of his brain that controlled his inner radio station had switched off, like it got that this was definitely not a good time for that. He hadn't sung or hummed once since they'd boarded the train, even since Ignis had put his foot down and Noct and Gladio had sort of stopped fighting.
The weird thing was he could swear he still heard the song, but it wasn't from in his head any more. It was creepy, really creepy, and not just because he thought he heard someone else singing the chocobo song when no one was around. It was creepy because he could swear it sounded like Ardyn's voice.
To top off all the shit and weirdness was the storm cloud gathering outside, it was the definition of dark and ominous, it totally didn't seem natural. The closer to Gralea they got, the weirder shit seemed to be. All the little things just felt off.
"What's going on?" Noct stood up as Prompto entered the dining car, he sounded thoroughly weirded out too. At least Prompto wasn't going crazy thinking something was wrong all by himself.
"It's a real mystery." He admitted, it felt good to say it out loud. "I'm not liking that snow cloud. Kind of gives me the chills."