Somehow, when they were assembling the skeleton, they did not notice it was more than eight feet tall. What they also did not notice, because this was too minute to be seen by the naked eye, was that there was text carved on every piece of bone.
When they put the last bone in place, the text shone for a few seconds, bathing them in green light, and the demon came back to life.
It was covered in tattoos coincidental to the text. It went home with one of them, ate her food, slept in her bed, talked to her mother, left clothes strewn about her place, till she got tired of it and shooed it off. Then it went to another one. This went on in a loop.
Then they killed it again, and distributed its bones across the country. They didn’t have good lives afterwards, but now they could put the blame on a curse and save themselves the effort of moving on.