Your Charisma score is increased by 1, and your Dexterity score is increased by 2

Your Strength score is decreased by 1

Your base walking speed is 30ft.

You have Advantage against being Charmed and Mind Reading Spells (Detect Thoughts and Scrying)

You have proficiency in the Deception skill.

You have superior vision in dark and dim conditions. You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can’t discern color in darkness, only shades of grey.

The doppelganger can use its action to polymorph into a Small or Medium humanoid it has seen, or back into its true form. Its statistics, other than its size, are the same in each form. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.

In the first round of combat, you have advantage on attack rolls against any creature you have surprised. If the attack rolls succeed, the target takes an extra 1d6 damage.

Each creature within 60ft. and line of sight of you must succeed on a Wisdom saving throw or become Frightened. Effect lasts for 5 minute outside of combat and 1 round during combat for a maximum of 3 rounds on consecutive failed Wisdom Saving Throws.

You can magically search for thoughts within 60 ft. of you. The effect can penetrate barriers, but 3 ft. of wood or dirt, 2 ft. of stone, 2 inches of metal, or a thin sheet of lead blocks it. While the target is in range, you can continue reading its thoughts, as long as your Concentration isn't broken (as if concentrating on a spell).

As an action, you can either shift your attention to another creature's thoughts or attempt to probe deeper into the same creature's mind, entering a trance-like state of concentration, where your movement speed becomes 0 and you are Blinded and Deafened to your physical surroundings. If you probe deeper, the target must make a Wisdom Saving Throw against your Charisma Score. If it fails, you gain Insight into its reasoning (if any), its emotional state and a brief, relevant vision. You can choose to probe even further into a targets mind regarding any information gained from the previous probe. The target must make a Wisdom Saving Throw and gains +2 to their save for each additional probe. If the target’s saving throw succeeds at any stage, the ability ends. Once the probe stops for any reason the ability ends and is regained after completing a Short Rest. If you use the ability but do not probe deeper, the ability does not require a reset.

You can speak, read and write Common