Abstract: An apparatus for applying a cosmetic, such as mascara to eyelashes, includes a handle, a stem, and an applicator head coupled to the stem and supported for rotation relative to the handle. An actuator moves the applicator head in a rotational oscillating motion, in which the applicator head automatically rotates in both a first rotational direction and a second rotational direction in response to operation of the actuator. Additionally or alternatively, the actuator may also radially translate the applicator head, move the applicator head through an angle of rotation less than 360 degrees, and vary the rotational speed-of the applicator head. The applicator head may include protrusions that are spaced to define gaps during rotation, thereby to promote coverage and separation of eyelashes.