Both nullify the damage they deal and take. Possession makes it a flying blocker. This one prevents all damage.
I worry about it costing 2 coloured mana. That can be rough to achieve. If you're putting this on your own creature it's worse than possession but on an opponents this is better. I'm not sure what to do with it.
Compare to Ghostly Possession: http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=220052
Both nullify the damage they deal and take. Possession makes it a flying blocker. This one prevents all damage.
I worry about it costing 2 coloured mana. That can be rough to achieve. If you're putting this on your own creature it's worse than possession but on an opponents this is better. I'm not sure what to do with it.
Changed the power reduction to keep it common.
Coded card into oblivion
Moved the ability to play spells from exile over to the land