Cloak (シャドー, Shadow) is a Mercury-class Utility Psynergy introduced in Golden Sun that costs 1 Psynergy Point. An Adept can obtain it if he or she is equipped with the Cloak Ball item, which you receive from Babi in Babi's Palace following the Colosso Finals.
The Cloak Psynergy causes the party to turn invisible while in a shadowy area. They will always materialize in light, however. It is used and required to complete the Lunpa Fortress sidequest, where it is used to sneak past patrolling guards in an instance of stealth gameplay. It is also used in Crossbone Isle, specifically the fourth floor, and that will allow you to progress through that floor's puzzle involving statues that block your path if they detect you. In that room, using both Cloak and Halt will also allow access to a chest containing the immensely useful Storm Gear.
The Cloak Ball and its Psynergy can appear in the inventory of Isaac's party in Golden Sun: The Lost Age if any form of data transfer is used. However, there isn't a single instance in the second game where the Cloak Psynergy is actually usable or useful.
||"Hide away in shadows." ((GS)/(TLA))||Become invisible to certain NPCs and traps while remaining in shadowy areas.|
|Utility Psynergy in Golden Sun and The Lost Age|
|Golden Sun||Avoid • Carry • Catch • Cloak • Douse • Force • Frost • Gale/Whirlwind • Growth • Halt • Lift • Mind Read • Move • Retreat • Reveal|
|The Lost Age||Blaze • Burst • Cyclone • Grind • Hover • Lash • Parch • Pound • Sand • Scoop • Teleport • Tremor|
|Restorative||Aura series • Cure Poison • Cure series • Ply series • Revive • Wish series|
|Mercury Psynergy in Golden Sun and The Lost Age|
|Elemental Base Damage||Blue Dragon • Cool series • Douse series • Frost series • Frost Card • Froth series • Ice series • Prism series|
|Elemental Phys. Attack||Call Zombie • Cutting Edge / Plume Edge • Diamond Dust / Diamond Berg|
|Support||Break • Cure Poison • Elder Wood set • Pixie set • Ply series • Restore • Succubus • Wish series|
|Utility||Avoid • Cloak • Douse • Frost • Lift • Parch|