MAC Haute & Naughty Lash

This mascara is designed to let you choose between volume and definition. The cap unscrews in two different places. Unscrew the top cap (pink), and it draws the wand through a narrower neck, wiping the brush clean for more defined application. Choose the blue/purple cap and the wand is drawn through a wider cap, which leaves more mascara on the wand.
I use the thicker wand on upper lashes and the thinner wand on lower lashes and it makes the eyes wide open. One coat is enough to give you crazy volume and length. I can't say much about clumping since I always go through mine with a comb, but I love it so far.