Jolt is a Jupiter Djinni found in Golden Sun: Dark Dawn.
When Set, Jolt increases its Adept's base HP by 9, base Psynergy Points by 5, and base Luck by 2.
When Jolt is unleashed in battle, the selected Downed Adept has a 60% chance to be revived, and their HP restored to 50% of their maximum HP.
In Dark Dawn, Jolt's unleash animation visually resembles the user summoning the 3D model of Jolt out of a lavender flash of light above the target as the camera swivels around and the background turns dark. Jolt crackles with electricity while a purple circular field appears on the ground underneath the Adept, and then a giant purple lightning bolt strikes the targeted Adept, transitioning into a purple field of fire-like energy that surrounds the Adept on the ground.
Golden Sun: Dark Dawn: Jolt is found on the Konpa Ruins dungeon early in the game, at the exterior roof area that you exit out onto while exploring the dungeon normally. First, you had to have cleared the room that gives you the Grip Crystal, and have equipped it to Matthew to bestow on him the Grip Psynergy in order to leave the room. Once back outside, go to the upper right and climb a ladder to an isolated spire, and cast Grip on the spire left of that to pull yourself left across a chasm. You will immediately see Jolt spot you and go up to the top of the roof. Follow it up there, and it will elude you for as long as you try to run after it. Approach it until it parks itself right next to one of the two spires, and then head back down so that you're parked next to the opposite facing spire. Remotely cast Grip on the spire next to Jolt to propel yourself into Jolt, knocking it aside and making it attack you. Defeat it in battle to add it to your Djinn collection. Jolt will be permanently missed once Konpa Cave is exited out of its south exit.
General: Jolt would be the least useful reviving effect in the game it appears in because there is only a 60% chance that a revive can occur, and even when a revive occurs it is only to 50% of the maximum HP meter. Other Djinn have both much higher chances to work and restore much higher percentages of HP, and there are also the Revive Psynergy and the Water of Life item that you can have easy access to later in the game, which have a 100% chance to revive to 100% HP. Jolt is strictly intended as an iffy, early-game means with which to try to revive an Adept that happens to have been downed and there are no Waters of Life or Sanctums around; in this regard, it has the potential to be useful.
Golden Sun: Dark Dawn: Jolt is found very early in the game at a point where the only Water of Life you could have found easily is the one that's the reward for beating the Psynergy Training Grounds twice (Patcher's Place sells a second one, but its 3000 coin price tag makes it way too expensive for your party to afford, unless you do an enormous amount of grinding to build up your money). Shortly after Jolt is found is the dangerous boss battle with the three Stealthy Scouts, and there is a very real possibility that one of your Adepts may be downed during the fight. Jolt, first of all, is very important to obtain so that it can be set on the Adept that has the other Jupiter Djinni Gust, and therefore improve that Adept's class to the second stage and increase all of that Adept's statistics. If another Adept is downed, Jolt can be unleashed to attempt to revive the downed ally at the expense of the user's own turn, and then Jolt can be used while on Standby to perform a small summon the next turn. If the revive fails to work, however, you will be put at a major disadvantage because the Adept that unleashed Jolt will have basically wasted a critical turn that could have otherwise been spent attacking. This is how the Water of Life can be useful in this fight, though at this early stage in the game you may want to instead sell the Water of Life for an enormous 2250 coins, so there is also that to consider. Ideally, neither reviving effect should be necessary, and Jolt and Gust remain Set on the same Adept to keep their class at the second stage.
After this battle, most of the rest of the game becomes much easier, and on the few occasions one of your Adepts may be downed, you have far better reviving methods to use like Waters of Life and the Revive Psynergy. Jolt's battle ability becomes obsoleted for sure once you get the Mars Djinni Cinder, which has a 60% chance to revive up to 60% HP, and Cinder in turn will be obsoleted later.