Animagus

After spending a long time with much practice and patience, you learn how to transform yourself into an animal and back again at will. You gain the following benefits:

• Choose one CR 0 Monster (beast) of your choice such as a cat or a raven. Once you choose a creature to transform into, you may never choose a different creature again. You may transform into that creature at will as an action requiring no spellcasting focus or materials. Maintaining this form does not require concentration. You choose whether your equipment falls to the ground in your space or merges into your new form.
• Your game statistics are replaced by the statistics of the beast, but you retain your alignment, personality, and Intelligence, Wisdom, and Charisma scores. You also retain all of your skill and saving throw proficiencies, in addition to gaining those of the creature. 
• When you transform, you assume the beast’s hit points and Hit Dice. When you revert to your normal form, you return to the number of hit points you had before you transformed. However, if you revert as a result of dropping to 0 hit points, any excess damage carries over to your normal form.
• 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.
• While in your new beast form, you gain the ability to comprehend and verbally communicate with other beasts. The knowledge and awareness of many beasts is limited by their intelligence, but at minimum, beasts can give you information about nearby locations and monsters, including whatever they can perceive or have perceived within the past day. You might be able to persuade a beast to perform a small favor for you, at the GM's discretion.
• 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.