- Cost to restore: 200 crystals
- Location: Shell
- Effect: After jumping, the user can press up to fall more slowly, but cannot open bags/chests or get items from breaking enemies. Leader Items and Drop Items are not affected.
This sealstone does not have any effect when set on a dais. However, it is necessary to be able to obtain certain items in this dungeon and later ones, notably the Seraphic Gate. In all these cases, a shell or a dais will be helpfully situated nearby to allow you to dispose of the sealstone and obtain the item. Restoring it is therefore recommended. A similar (albeit not identical) sealstone can also be found in the Seraphic Gate.
The name of this sealstone is somewhat puzzling. "Cap" may refer to the device used in toy guns, in which case "powerless cap" could be comparing the user to a spent explosive (all it can do after detonating is fly). "Powerless" refers to the inability to obtain items.