Disclaimer – I don't own either the Legion of Superheros or Buffy. I am not making any money off this story. And to be honest, who would pay to read this silliness. Dang muse just won't focus.
Timeline – BtVS – high school years
Legion – After about 100 reboots (20 in the last year alone) who really knows anymore. Figure sometime during the early days – when they were still teenagers.
He Can Eat Anything
"The Crystal of Davarosa will explode in three minutes," Giles said.
"Can we stop it?" Buffy said.
"There is no way to stop it."
"You talkin about thecrystal over there?" a man asked.
"Who are you?" Buffy said.
"Tenzil Kem, Chuck said you were cute. I had to see for myself."
"Now is not a good time," Giles said. "The world is doomed."
"No problem," Tenzil said. He picked up the crystal and popped it in his mouth. Giles and Buffy stared as he chewed up the crystal and swallowed it.
"My God," Buffy said. "He can eat anything!"