Potion of Stable Form

This aromatic potion is brewed from the white flowers and black roots of the magical herb moly. When you drink this potion, it immediately attempts to counteract all hostile Transmutation effects affecting you. For the next hour, you gain an item bonus against transmutation effects, which is greater against Polymorph effects. If you roll a success against a polymorph effect during that time, you get a critical success instead.

The counteract level is 5, and the counteract check modifier is +17. The item bonus is +2, or +3 vs. polymorph.