Lykoithropy

Your body has contracted Lykoithropy , a feline version of lycanthropy, which causes your body to involuntarily change into a monstrous version of yourself when subjected to the full moons light or by your own choice.

As an action, you may transform into a monstrous hybrid: half-beast, half-sentient. While in your hybrid form, the following rules apply:

• You can’t cast spells or concentrate on spells. Your ability to speak is reduced to short, basic, guttural responses.
• You gain 60 ft of extra Darkvision.
• You gain an additional 20ft. of speed.
• You gain temp HP of your Constitution modifier x 15.
• Your strength is increased up to 16 and your dexterity stat increases by 2.
• You gain resistance to bludgeoning, piercing, and slashing from non-magical weapons.
• You gain vulnerability to silver and moon touched weapons which cause you great pain and discomfort.
• Any armor you are wearing is affected by your transformation, getting torn, falling off, or getting stuck to your Hybrid Form depending on the materials and compatibility with your new form.
• While transformed and not wearing any armor or using a shield, your AC is your strength modifier + dexterity modifier x 5.
• While transformed you cannot use martial weapons or shields.
• Your hybrid form can last for a number of hours equal to your Constitution modifier (minimum of 1) and ends early if you are knocked unconscious or reduced to 0 hit points. You can try to end your Hybrid Form early by using an action on your turn and making a Constitution save (DC = 14).
• You gain two new attacks with your hybrid form:
  • Claw Attack: 1d6 slashing damage + strength modifier - You may use this attack as a bonus action allowing you to claw twice or claw and then bite. This attack's damage increases by 1d6 when you reach 5th level (2d6), 11th level (3d6), and 17th level (4d6).
  • Bite Attack: 1d8 piercing damage + strength modifier - After a successful bite attack you may use your bonus action to make your target do a Strength Save (DC = 8 + your proficiency bonus + your strength modifier) or be knocked prone. This attack's damage increases by 1d8 when you reach 5th level (2d8), 11th level (3d8), and 17th level (4d8).

 The savage nature of your curse sometimes causes you to lose control. These ferocious tendencies are a constant struggle between you as a humanoid and the beast within. When you are in your hybrid form, you must succeed at a DC 10 Constitution saving throw at the beginning of each turn or lose control. If you are in the light of a full moon, you automatically fail this saving throw. If you fail this saving throw, you are subjected to the following until you succeed:

• You must move toward the closest nonplayer creature you can see, smell or hear, prioritizing easy prey. If you end your movement and no non-player creature is within 5 feet of you, then you must use your action to dash toward one.
• If there is a non-player creature within 5 feet of you and you have not used your action, you must make a melee attack against it, prioritizing easy prey.
• If there are no non-player creatures within 60 feet of you or you cannot see any non-player creatures, you must attack the closest player character.
• If you made a melee attack against a creature, and that creature is still alive, then you must use your bonus action to make an unarmed claw attack against the same creature.
• Additionally, if you are subjected to the light of a full moon when not in hybrid form, you must succeed at a DC 20 Constitution saving throw or automatically turn into your hybrid form and cannot transform back until dawn. If you succeed in this saving throw, you are immune to its effects for 24 hours. If a player offers you words of encouragement such as reminding you of who you are, telling you that you can fight it, etc., etc., you may roll this with advantage (Don't ask a player to do this for you so you get advantage. It should be their decision so it works for better RP). 

Optional Rule - Animal Instinct: You also attack player creatures that fit into the category of easy prey.

EASY PREY

A creature that is unconscious, restrained, prone, blinded, paralyzed, frightened or bleeding profusely. The DM may consider other circumstances that would define a target as easy prey or not (children, weakly humanoid, disarmed targets, surrendered enemies, etc.)