I have so many concealers that I assign to different parts of my face, at different times of the year, and for different occasions. I have learned to fit Benefit's Erase Paste into the rotation when I need to cover really dark undereye circles. This beauty makes them disappear while lightening and brightening up the whole area.
I am not sure where my little spatula disappeared to because I have got myself digging out the "paste" with the end of a concealer brush. I then flip the brush to spread it - even though it is easily spreadable with a finger.
Unlike a conventional, thinner concealer made to be lighter than your skin tone, Erase Paste is thicker to stay where you spread it. It is also pink based, making it appear more natural and a bit highlighter, thus diverting more attention away from the flaw. I am using medium right now, but will surely try it out in fair for the non-tanned months. There is also a deep shade available, for darker complexions.