imagination running wild

My 2.10yo is having weird thoughts about our ceiling lately. And they only occur when it's time to say goodnight. He no longer sleeps in his room, or if he would, he would sleep on the floor where he would bury his face with his pillow. Other times, he would request to sleep in my parents' room where he would first do a ceiling checkup.

It was crazy, seeing him cry like there was really something going on up there. He would tremble and scream while I can only assure him there's nothing to worry about and that I would never leave him and while I'm around, nothing will harm him. But I don't think he hears me. Even if I think it was all nonesense, I can't let him see that I'm taking his fears lightly and at the same time, I must be firm that his imagination is no biggie.

One night, I said hi to whatever-that's-up-there. He couldn't believe what I just did. And I declared that I am now their friend. He continued checking up the ceiling and then decided that they left. I hope I scared them away.