Can you swing a pig weighing your max load?

[malonkey1]

Except you have to first be ethereal to posses somebody. Since the ethereal is a whole plane away from where the pig is, than for that moment, you fail to meet the conditions. So it turns into porcus, and reaches through the ethereal to skin you.

Except that the Ethereal Plane is coexistant with the Material Plane:

http://www.d20srd.org/srd/planes.htm]Coexistent Planes
If a link between two planes can be created at any point, the two planes are coexistent. These planes overlap each other completely. A coexistent plane can be reached from anywhere on the plane it overlaps. When moving on a coexistent plane, it is often possible to see into or interact with the plane it coexists with.