Fantasy roller coaster/theme park ride ideas you've had

What are some strange, crazy, insane, or possibly unrealistic/impractical ideas for park attractions/roller coasters you had thought of, maybe as a little kid or just now, that might sound awesome on paper but they probably might not work in real life (or maybe they would but have not been built yet)?
My list:
-Hourglass tower-take an S&S drop tower and put it inside a rectangular steel frame that's attached to two support towers similar to a Top Spin. The steel frame rotates vertically at a constant speed similar to those Sky Swatters (or whatever they're called), and the gondola, which moves freely up and down the tower via gravity, keeps dropping down to the bottom of the steel frame, similar to the sand inside an hourglass, alternating between right side up and upside down. There would probably be magnetic brakes to prevent the gondola from crashing into the steel frame.
Sorry for the lengthy description. I would have made an animation if I knew how.
-Upside down drop tower-exactly what it says on the tin. The one thing I didn't think about was how riders are supposed to get in.
-Something that looks like a swinging pizza slicer-exactly like Delirium at Kings Island, except the gondola is parallel to the swinging arm, so it looks like a giant pizza slicer.
-5D coaster-a regular spinning coaster car with two freely spinning seats on each end, and they spin vertically.
-4D drop tower-a drop tower ride that has seats that rotate on an axis in the same way that 4D coasters do, and it's a controlled spin.
-This is one I thought of recently: the world's first support-less roller coaster. It's just a coaster track that levitates inside a strong magnetic field and thus does not need a structure.

Oh well, I had the concept of a spinning coaster that starts with a launch into a toilet bowl where it do a few helices. It would also incorporate a Heartline Roll and a overbanked turn. Fittingly the ride would be called Royal Flush. I think I once mentioned it in a thread on CC a few years ago.