Grape 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 and later released in Japan in 2011, only to be discontinued a year later.
(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.
On January 26th, 2011, Suntory announced they would release Mountain Dew Grape for the Spring of 2011 in 355ml (U.S. 12-ounce) cans. It featured a moderate sweet flavor and a purple packaging color that was made to stand out in vending machines.
Its planned release of April 2011 was delayed due to the Tohoku Earthquake, and it was eventually released a month later on May 24th, 2011. As noted, it was sold in certain Japanese vending machines, mainly Boss.