Has it ever happened to you? Or maybe what I experienced wasn't hypnagogic hallucinations, really. I'll desrcibe it in more detail:

I was trying to fall asleep, and after 5-10 minutes of lying still I had a 'mini-dream'. It wasn't really a hallucination, it was just a very short dream, lasting for 5-10 seconds which was so hilarious that it made me laugh.

Precisely, I dreamed of some two devils, in the sense that the not necessatrily looked like devils (I don't remember their appearance) but for that moment I considered them as devils. They were arguing, or something like this. And then one of the devils tricked the other one in some funny way, played a prank on the other one, you know. I just laughed at it, and quickly realised that I was dreaming, and the vision faded. Isn't it interesting?