Retreat

Retreat is a Venus class Utility Psynergy usable in both Golden Sun and Golden Sun: The Lost Age that costs 6 Psynergy Points. It is a Psynergy that is inherently known by both of the Venus Adepts and party leaders within the games, Isaac and Felix. The Retreat Psynergy causes the party to "Return to the dungeon's entrance," and is a very practical spell that can be cast at almost any point in almost any dungeon-style location.

Analysis
While not actually a Psynergy that is mandatory to beat either game, it can be a huge boon to any party wanting to leave a dungeon without having to backtrack through it. One of the best examples of this is the Tundaria Tower dungeon, where the true prize is located at the beginning but can only be obtained with a special item found at the top. Another good example is after Isaac and Garet first meet with the Wise One and learn that the Sol Sanctum is about to collapse and are told to exit the dungeon. As there are no enemies during that segment, meaning no chance for experience, using Retreat here saves some time. It can also be useful during the beginning of a game, if your party of Adepts are injured and you need to return to an inn and want to avoid as many monsters as possible.