I think this realm holds too much substance for physical shifting. Its too heavy and not as flaint as astral or other realms. Human bodies can't physically take shrinking and stretching and morphing like that. If it was possible it would be so much painful because you have to think about organs rearranging.

It this world wasn't so dense then maybe. I do think that peope can go into a very deep mental shift that would think that they can physically shift because if the shifting energies. There are a few natural things that happen though. Like eye color changing.

But thats my opinion.