True.. but we also may want to have the starfish start where he last was. Having him reset to the default start makes if look like he seldom moves far. Without my three possibilities I don't see how to make the transition from glass to sand.. Unless you came up with a distraction.. On reaching the glass / or sand you created a disturbance.. a cloud of swirling sand ?? and when that cleared the starfish had made the transition.. how realistic that would be would depend on your magic