The Happy Trigger is a new item introduced in Kid Icarus: Uprising. It is found throughout the game and decreases the charging time between separate charged shots so Pit can fire charged shots at a faster rate than before. They are notably found in both air and land battles and are commonly found by shooting Treasurefish. They can also be found in Treasure Boxes and simply lying on the ground. It can be used in both Solo and Together Mode.
In Kid Icarus: Uprising, the Happy Trigger simply looks like a small, golden, pistol like gun with wings attached. Also, the weapon can only be viewed in 2-D. The idol description in the game says, "The Happy Trigger cuts the wait between charged shots. The ability to fire off a rapid succession is valuable for weapons with long charged times."