Whether through lycanthropy, shamanistic rituals, foul magic, or some other means, you have the ability to change into a specific animal form. Choose a small or medium beast CR 1/2 or less that doesn't have a fly speed. As a bonus action you may assume the shape of that beast or revert to your normal form. While you are transformed, the following rules apply:

• Your Strength, Dexterity, and Constitution scores, as well as Armor Class and Speed change to those of your new form.
• You gain any of your new form's skill proficiencies, special senses like darkvision, and traits such as Keen Smell or Pounce.
• You replace your unarmed strike damage with any attacks granted by your new form if they are better. You do not gain multiattack.
• You use your own hit points and hit dice, even when transformed.
• You can’t cast spells, and your ability to speak or take any action that requires hands is limited to the capabilities of your beast form. Transforming doesn’t break your concentration on a spell you’ve already cast, however, or prevent you from taking actions that are part of a spell, such as call lightning, that you’ve already cast.
• You retain the benefit of any features from your class, race, or other source and can use them if the new form is physically capable of doing so. However, you can’t use any of your special senses, such as darkvision, unless your new form also has that sense.
• You choose whether your equipment falls to the ground in your space, merges into your new form, or is worn by it. Worn equipment functions as normal, but the DM decides whether it is practical for the new form to wear a piece of equipment, based on the creature’s shape and size. Your equipment doesn’t change size or shape to match the new form, and any equipment that the new form can’t wear must either fall to the ground or merge with it. Equipment that merges with the form has no effect until you leave the form.

Once you have shifted into a beast in this way, you can't again until you finish a short rest.