"Doctor's" Mask

Shifting Stitches. This mask adapts to the chosen style of the wearer, and it's style can be altered by the wearer once per long rest, if they so choose.

Summoner's Sagacity. This ability allows the wearer to assume total control of one of their controlled or summoned creatures. The wearer transfers a slice of their consciousness to the chosen creature, allowing them to control the body as if it were their own. If the wearer casts a spell while using this feature, the spell may be cast from the controlled creature. The level of the spell available through any given creature is equal to half of its total CR (Challenge Rating), rounded up. Spells of 6th Level and higher cannot be cast in this way.

This connection lasts until broken by the wearer, or if either the wearer or the controlled creature are Incapacitated.

Legionnaire's Link. The wearer can designate groups of summoned and/or controlled creatures into 'squads'. 

Absolute Awareness. If any of the wearer's controlled and/or summoned creatures take or deal damage, the wearer receives a gentle psychic nudge. The wearer designates separate signals for taking/dealing damage. This ability can be toggled on/off.