So I was wondering, has anyone created a puzzle that starts in the form of a cube, but when manipulated, ends up as a pyramid.

I think this would be an awesome challenge for someone with the knowledge or skill to do it.

Has any puzzle been created like this at all? Where it starts in one shape and can be manipulated to a different shape?

Another puzzle idea I was thinking about is, two separate puzzles that can combine. In other words, separately, they would function like any other twisty puzzle. But you could also combine them to make a completely new puzzle (maybe a siamese puzzle, maybe something completely different). Combining them would not be a mod, it would be possible the way the puzzle already came.

I like your wild imagination - these are the kind of ideas that people say can't be done ... until somebody like Tom or Oskar makes them just a couple of years later.

They should probably join these.

PS. I think your second idea should be possible - to create an interlocking burr puzzle, where each piece is a shape-shifting twisty puzzle, and must be solved into the right shape before it can be interlocked with the other pieces.

Your second idea is a lot like the "child's play" puzzle. But it's a little different. I think it would be fun to have to 3x3s connected by an elastic cord to look like a 3x3x6. You could then stretch the cord to turn each cube individually.

I could imagine Oakar's gift cube, where the lid becomes a floppy cube when removed...

I'll definitely post my ideas there. Or if a mod wants to move this thread into that one. That's be cool too.