Orange is a Mountain Dew flavor first released as a flavor shot in a test market release of a touchscreen soda fountain machine called Pepsi Fusion (designed to compete with Coca-Cola's Freestyle machine) for a short period in 2010.
Mountain Dew Orange is (as its name suggests) a Orange flavor of Mountain Dew, and is orange in color. It is similar in flavor and color (both orange) to two other orange Mountain Dew flavors, LiveWire and Game Fuel (Charged Orange Storm).
(2010) Pepsi Fusion test market release
In 2009, Coca-Cola released a touchscreen soda fountain called the Coca-Cola Freestyle. A year after, PepsiCo quickly responded with an equivalent touchscreen soda fountain called the Pepsi Fusion, designed to compete with Coca-Cola's Freestyle machine.
PepsiCo then conducted a test market release in 2010 in various restaurants for a short period of time. The flavors available in the Pepsi Fusion machine were Lemon, Lime, Grape, Orange, Cherry, Strawberry, Raspberry, and Wild Berry, eight flavor shots.