Double Rainbow

Double Rainbow is a player vs. player achievement earned for performing a  emote under the double rainbow in the Battle for Gilneas.

It is easy to tell when a player is in the proper position, as it will actually tell the player they have entered a zone named Beneath the Double Rainbow.

Trivia
The zone and the associated achievement are a reference to the now famous Youtube video of a man video taping a Double rainbow in the distance of Yosemite. Following this, he proceeds to somewhat over react, even going as far to start breaking down into tears of joy.