Introduced in the Von Drakk Manor expansion, emergency Potions are denoted by a Green potion icon.
An Offensive Potion provides a model with an single use special action or special attack. These effects follow all normal rules for resolving special actions and attacks, including being able to target enemies and requiring attack and defense rolls (if the potion provides a special attack). They require no action points to use and are instead used by spending a potion token in the same manner as a normal potion, but may only be used during a model's activation.
For a complete list: Offensive Potion