Captain's log - Stardate 2261.411

Our visitor called himself Alcero. He was a nervous sort, but he hadn't annoyed me, so I let him live.

After a few hours of watching Bones discretely taking tricorder scanning of him and Spock trying to see why his tricorder hadn't shown Alcero's existence, he spoke up and said he knew we were from outside. Then he told about how, when he was much younger, he had climbed the forbidden mountains and touched the sky. Almost immediately, he screamed and grabbed his head. He was dead within seconds, but why?