Introducing the concept of Targets. or maybe Waypoints is a better name.
If you want an object to move around on it's own, you first set down a waypoint. Then place the item on top of it. This is the starting point of your path. When you place more waypoints, the object will begin to move to the closest one. LIKE MAGIC

There are 5 types of waypoints

1) Move to the closest target.
2) Move to the closest target that is NOT the one you just came from.
3) Go to the first target you started at.
4) STOP
5) Move to the closest target when the player touches the object.

Only certain items will work with the waypoints:
PLATFORMS (simple flat things to stand on)
SWITCH BLOCKS
FISH
SPIKE BALLS

Fish will swim back and forth when in water and kill you if touched. Out of water they will siezure in place unless they are on a path.
Spike Balls are simple but deadly, they will fall down with gravity if not on a path.

Moving platforms may have issues and unforseen side-effects. Use at your own risk.