Ectoplasmic Feedback

You are warded in a thin layer of energy that protects you from incorporeal creatures. This spell causes any incorporeal creature to be rebuked upon trying to pass through you. Such creatures that hit you with their natural attacks (like the Specter's life drain) are subject to 1d8 points of force damage. Incorporeal creatures that attempt to pass through you or possess you are also subject to this damage. Additionally, movement is immediately halted and your saving throws against a possession have advantage.

In the case that the trigger for this damage causes you to lose concentration on the spell, it does not end until all effects related to that trigger are resolved. In the case of multiple attacks from multiple creatures at once, it is up to the judgement of the DM as to whether to resolve concentration checks one by one or as a whole after all are affected.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage of the spell increases by 1d8 for every level above 3rd.