Ghost Form

Your form becomes shadowy and incorporeal by splitting it across the physical and aetheric realms.
You can squeeze through any non-airtight space, fly at half speed, and float. Strong winds may blow you around. You may pass through spaces occupied by enemies unhindered. You may pass through walls and solid objects unhindered, but if you end your turn inside a solid object, you take 100 physical damage.
You cannot be immobilized, restrained, grabbed, tripped, pushed, or pulled, except by silver.
You are partially concealed from normal sight, heatsense, and lifesense. You are concealed from tremorsense.
You have advantage on tests of Roguery.
You resist physical and dark damage, but are weak to silver weapons and light damage.
Touching silver objects causes you to take damage.
Physical damage you deal is halved, unless it is from a spell.

Other than with the objects that were on your person at the time you transformed, you will have difficulty picking up, carrying, pushing, pulling, or interacting in any way with any objects that require more than the smallest amount of force to do so. (You can lift sheets of paper without a problem. Turning a doorknob or picking up a candlestick requires a test of Strength.) You have -10 on all tests of Strength because you are a ghost.

You cannot normally dismiss this spell. Reconstituting your body requires taking a rest (unless you upgrade this spell to allow you to end it as a fast action).

Being in ghost form puts you half in the physical and half in the aetheric realms. As a result, you can weakly interact with things in both realms and the resistance from this ability applies to things in any realm, including things banished to an aetheric realm by the Banish spell.

Subtle:
Casting this spell while hidden does not cause you to become unhidden.

Suggested Backfire: You become weak to physical damage and dark damage.