Yup.
If it's between being awake and sleeping, they're called hypnogogic hallucinations.
If it's between being asleep and waking, they're called hypnopompic hallucinations.

If they are either of those, not to worry. They can happen to "normals" too. Also, don't worry about the word "hallucination" in them. They are harmless, and not of the sort we usually talk about. Regardless, they can seem VERY real! (I've even gotten out of bed and walked a bit to touch them! And yes, before I learned of these, their happening freaked me out.)

If they aren't those, or you are otherwise concerned, talk to your Pdoc.