Polybrachia

3rd-level conjuration
Casting Time: 1 action
Range: Touch
Components: V, S, M (a pair of armbands)
Duration: Concentration, up to 10 minutes
Two muscular arms consisting of brilliant arcane energy appear on a willing creature that you touch. These arms are fully functional and can be used to hold weapons and shields (allowing the target to hold 2 two-handed weapons, or 4 one-handed weapons), perform somatic components of spells, and perform other actions, though the arms themselves don't grant the target additional actions. For the duration, the target has advantage on Strength (Athletics) checks made using the additional arms. Also, if the arms are used to carry weapons, the target can use a bonus action to make an additional melee weapon attack using the arms.