My grandfather became a ghost

Esben had a grandfather, whom he simply called Grandpa. One day Grandpa was gone, because he died. Esben’s mother said that Grandpa had become an angel. Esben’s father said that Grandpa had become earth. But both father and mother were wrong, because one night Esben suddenly saw Grandpa on his chest of drawers: he was sitting and staring motionlessly into the darkness.

“Grandpa?” Esben asked. “How did you end up here?

I thought you were dead.”

“I thought so too,” Grandpa replied.

“Oh! You’ve become a ghost!”

“Something like that,” Grandpa agreed.