goop beauty Featherlash Mascara is a lash serum and mascara in one. The formula lifts, defines, and volumizes, giving lashes a naturally full look. Lashes are nourished with each application and the rich pigment doesn't flake or smudge. The product supports lash health, conditioning for lush, healthy-looking lashes. A patented brush head with three-edged cross sections also helps to enhance definition.