don't worry, all of those are just dream's game ;) . try imagining , you dream , you fall into these holes , a big black hole with no ending , so you scream until .... you fed up but you find yourself still falling, wake up from your dream ? you can't !
Like Sebastian in The Little Mermaid?
check ep "dreams"
I don't know... But I had one like that a couple of weeks ago and I had to walk sideways so the crabs wouldn't attack me :O