Skeletons

The sleepy locomotive lumbered down the tracks, full of people dressed in clothing that doesn't quite fit this era. One man in particular stands out, and to say he is overdressed is a colossal understatement. The genteel man stood up and removed his glasses. He looked directly at Scott and boldly said, "Scott, this is going to shock you, but you are the only human on this train."
Mouth agape. Eyebrows low. Tongue drying.
"Just not a funny thing to say," he cooly replied.

It was snowing harder, and the air was getting thinner. It was also glowing harder, literally. The entire landscape was illuminated in a dull green light that transversed every gentle curve of the mountains. Scott never noticed it.
Seriously, any human that wasn't aware of the aliens had to be an idiot. Nobody actually said anything about their permanent residence, but it was just understood. Spacemen had been living amongst people for years, it was a plain fact! It didn't need any explaining! The giant eyeballs were sort of a dead giveaway at least.

"Freaks," he secretly dubbed them. Or "Mutants and nerds," which was a more frequent term when he was surrounded by friends. I suppose he never realized that he was talking to some at that very moment. They first arrived when he was a child, but there had been visits for many years before that. Actually, his parents were both from Vesuvius 81, a planet not far from the Milky Way. They migrated to Earth 42 years ago in search of a better life.

They had been on Earth for a total of six minutes when they adopted Scott. He was resting on a street corner, swaddled up in a brown blanket (which was not originally brown, but was in fact redesigned by a robust Swedish man hoping to turn a profit).
This ugly little baby taught these aliens an invaluable trait that skeletons don't know by default.
Disgust.
Every alien fully understands every conceivable emotion and idea EXCEPT for disgust. The baby puked the instant they touched him, and the aliens had absolutely no idea how to react. At first they laughed, but then got embarrassed because they knew that response simply did not fit. The Vesuviusians let him simmer down for about 14 Earth minutes before they picked him back up.

That was very relevant. Scott did everything in intervals of 14 minutes. It took 14 minutes for the importance of the locomotive situation to fully set in. He put down the newspaper he had been barely reading and stared intently at the floor. "Skeletons," he mumbled, "Skeletons!" He stood up and screamed in absolute horror. His uninterrupted screaming disturbed every alien on the bus. He only stopped to gather more air.

An incredibly muscular, blonde Swedish man burst into the train doors wearing a look of intense concern. "My God!" he whispered. His feet were lighter than air as he galloped down the aisle toward Scott. "My precious boy, it will be alright if you just trust me with all of your might!" were the only words he said for the next 14 minutes. Scott wasn't as much concerned with him as he was the "skeletons" he raved on about. The Swedish man cooed and floated around Scott, as if he were afraid to touch him. Finally, he laid a single finger in his knapsack and pulled out a string of silver thread. "Make ten wishes and none will be granted," he said in a tone just short of piercing silence.

He touched Scott and he vomited.