[Prism]

Golden Plume:
Basically an infinite Alga Plume in the vein of the Golden Pickaxe/Lockpick.

Added feature (and probably the main reason for having it): Ability to return to the spot you last used it while inside the dungeon/the floor on which you used it (perhaps a dialogue box when entering said dungeon), something along those lines. Basically gives you and your party a chance to easily get out of the dungeon, heal, fix your weapons, etc, and get back in without having to retread your territory.
But if the dungeon despawns while you do this, bad luck? Unless using it keeps the dungeon from doing so, though I dunno if this would cause issues or not.