How to create shape shifting mesh like in Soul Reaver when shifting between worlds?

In Soul Reaver series Raziel could shift from Real World to Spirit World. This shift was a real time effect that was changing lighting and mesh of some terrain (like moving platform up or moving bridge gap together so player can cross it or opening cavity in the ground). Lightning can be put on different Layers but what about shifting mesh? I was thinking on getting animated mesh and playing animation for it. What about mesh collider of this terrain mesh? Can it be done by changing mesh in mesh collider with script and during transition moving player to new position by script (with physics off). Do you think that this solution is a good approach? Can you think of better solution?