When you get afflicted by this curse you become imbued with the monstrous essence of the Owlbear.
The curse has a specific trigger, typically the occurrence of a full moon.
Upon rolling a natural 1 or natural 20, you automatically transform.
When transforming due to the trigger or a natural roll, you must succeed on a Wisdom saving throw with a DC of 10 + your player level. Failure results in entering a rage, compelling you to attack the nearest creature as your sole action. You can repeat the saving throw at the beginning of each of your turns.
Monstrous Might: Your Strength score increases to 20 if it is not already higher.
Keen Sight and Smell. In your humanoid form, you have advantage on Wisdom (Perception) checks that rely on sight or smell.
Monstrous Trait: While under the influence of this curse, your non-dexterous hand is transformed into the feathery claw of an owlbear.
Owlbear's Barb: As an action on your turn, you can launch spikes from your owlbear tail. Use your Strength modifier for the attack, and the spikes have a range of 100/200 feet. You are proficient with your tail's spikes, dealing 1d8 + Strength piercing damage.
Owlbear Form: As a bonus action on your turn, you can transform into a owlbear, adopting its stat block for 1 hour. Your hit points and Hit Dice remain unchanged. You can revert to your normal form as a bonus action on your turn. Once you use this feature, you can't use it again until you finish a short or long rest. You revert to human form if your hit points drop to 0 or if you die.