Dazai under no circumstances believed in spirits, ghosts, poltergeists, whatever you called them.

His friends had visited, and during their stay, dared him to summon an 'incubus' since he thought it was all ridiculous. He did so. Nothing happened. He scoffed.

After they'd left, he'd gone to bed, not taking long to fall asleep.

He's awoken by something pressing onto him, his eyes opening to see a... person? No. It looked human, but it wasn't. He stares in surprise. An incubus?