Substitute

You surrender a quarter of your current HP (rounded down) into temporary hit points in the form of a shield. During this time, the shield grants you immunity to NEW negative conditions (including things like prone, restrained, etc.) and it absorbs all outside damage that you would normally take until it is destroyed. The shield is considered "typeless" for damage resistance, vulnerability, and immunities. The shield and user cannot be healed while active, and it does not absorb self-inflicted conditions or damage caused by pre-existing burn, poison, or confusion. The shield breaks when it is reduced to 0 hit points, and the user takes the overflow damage. Sound- based moves bypass the shield (Supersonic, Grass Whistle, etc.)