Manikin of Lightning

You are made of inanimate material but have been given life and a soul, making you a living being for the purpose of all effects that require it. You are a Humanoid. You are also considered a Construct for any prerequisite or effect that requires you to be a Construct.

Ability Scores: As a bonus action you can attach yourself to a willing creature you can see within 30 feet of you via a set of immaterial strings for 1 hour. If the creature you're attached to doesn't use all of its movement on its turn (if it has multiple movement speeds, pick the highest one), you can use your reaction at the end of the turn to move a number of feet equal to its remaining movement. In addition to this, you can grant the use of your reaction to the attached creature and vice versa. This means you or the attached creature could use one additional reaction on their turn, but then the other one does not get to use their reaction. While attached in this way, you can also telepathically communicate with the creature. To do so, you do not need to share a language, but both of you must be able to understand at least one language. Once you attack yourself to a creature in this way, you can't do so again, until you finish a short or long rest.

Feat: Your body can be upgraded with built-in defense layers, which determine your armor class. You gain no benefit from wearing armor, but if you are using a shield, you apply its bonus as normal. Through 8 hours of work in a specialized workshop, you can alter your defensive layers to any armor type or back into your Unarmored state. To do so you require an undamaged armor of the type you want to upgrade your body with, with which you need to be proficient. By doing so, you gain the effects of wearing the armor (e.g. Armor Class, magical benefits or Disadvantage on Stealth checks), but the armor itself and therefore its weight becomes part of your body.

Unarmored. Your AC equals 11 + your Dexterity modifier.