Combat Mimic

Others’ skills are your greatest weapon.  When you take this feat gain the following abilities:

• On your turn, as an action you can choose to observe and study an enemy on the battlefield.  After doing so you are considered proficient with their weapon for the next minute.
• As a bonus action after studying an enemy, you may choose to attempt a sleight of hand check, contested by their perception, to steal the weapon from the enemy’s hand(s).  On a failed roll you do not steal the weapon and the enemy may hit you with their weapon for a 1d4 of damage.  On a success, you steal the weapon and may immediately make one attack.
• For the purposes of sleight of hand checks to disarm an opponent you are considered proficient.  (If you already have this proficiency, you are considered to have expertise when rolling to disarm.)

Choosing to study a different opponent or fighting style will result in the user losing proficiency with the previous weapon.