ColourPop Viper is a very warm-toned, dark purple with a matte finish. It is a permanent lipstick that retails for $6.50 and contains 0.11 oz.
ColourPop Viper Ultra Matte Liquid Lipstick ($6.00 for 0.11 fl. oz.) is a deep, medium-dark plum with subtle, warm undertones and a matte finish. The color was fantastic, and it's more unique than not, but there was something amiss with the formula, as it dried down and some areas were darker and pinker and other areas were grayer. It was like an ombre lip look gone bad! I thought it hadn't dried down, but it had (no transfer and didn't look different hours later). It applied well from the tube, and the product was fully opaque on the lips. The texture was clingy, and it did have noticeable "cracking" when I smiled; I could definitely feel I was wearing a liquid lipstick. This shade stayed on for over six hours with minimal changes in color/intensity, but it was drying. Marc Jacobs Beauty Vinyl Dream (P, $30.00) is glossier (90% similar). Makeup Geek Tomboy (P, $12.00) is lighter, cooler, glossier (90% similar). ColourPop Are & Be (P, $6.50) is darker, cooler (85% similar). ColourPop Lumiere 2 (P, $6.50) is lighter, cooler (85% similar). Makeup Geek Urbanista (P, $12.00) is darker, cooler, glossier (85% similar). NARS London Calling (P, $26.00) is darker, cooler (90% similar). MAC Oh Lady (P, $21.00) is darker (85% similar). MAC Evening Rendezvous (LE, $20.00) is lighter, cooler (80% similar). NARS Dirty Mind (P, $27.00) is darker, cooler (80% similar). ColourPop Bad Habit (P, $6.50) is lighter, brighter (80% similar). ColourPop Back Up (P, $6.00) is lighter, cooler (80% similar). ColourPop Bijou (LE, $7.00) is cooler (80% similar). MAC Winifred (LE, $20.00) is darker, cooler, glossier (80% similar). See comparison swatches / view dupes side-by-side.
FURTHER READING: Formula Overview, which is a detailed review of the range as a whole.