Sounds like good ol' hypnagogic hallucinations. Sometimes HH can be very intense, like when it's coupled with sleep paralysis, or it can be milder, like when your just falling asleep. I get this a lot, especially when I'm sleep deprived or if I've been up tossing and turning.

If you want to turn these "visions" into a lucid dream I HIGHLY suggest you do not try to do it when your first falling asleep. Get atleast 4 -6 hours of sleep in, wake yourself up and then try going back to sleep. Your head should still be sleepy yet you should have more clarity then when you first fall asleep. Once you start seeing things at this point, keep lying still until you can't even feel yourself in bed or you feel the "shift".

Look around the WILD forum for some tips on transitioning HH into a LD. Good Luck