Very Rare Adventuring Gear (Smith’s Tools), Requires Proficiency with Smith’s Tools, Requires Attunement

The Tongs of Thousand Forms is the upgraded version of the Mercurial Tongs, it keeps all of its original stats, but its ability check bonus is increased to +4, Mercurial items gain additional properties and you gain the ability to turn magical items Mercurial.

• When used as part of Smith’s Tools, it gives a +4 bonus on ability checks made with them. 

Essence of Quicksilver. When you finish crafting a non-magical item using the Mercurial Tongs, you can make it into a Mercurial item, giving it the following properties for 24 hours based on its item type. If an item loses its Mercurial property, it transforms into an ordinary non-magical version of their original item type. 

• Mercurial Weapon or Shield. A creature wielding this item can use their bonus action to transform it into any ordinary simple or martial weapon, or a shield. These items become magical +1 versions of their type as long as they are Mercurial.
  • Elongated Form. As a bonus action, you can increase the reach of your Mercurial Weapon by 5 ft. until the start of your next turn
    • (Recharge 5-6). When your Elongated Form feature is active, before you make a weapon attack with the affected weapon, you can massively increase its size, allowing you to make a single attack with that weapon against a different creature within 5 feet of the target as well, as long as they are within reach or range. 
  • Silvery Barricade. As a bonus action, you can increase the size of your Mercurial Shield, allowing you to provide ¾ cover to creatures behind you until the start of your next turn. 
• Mercurial Armor. A creature wearing this magical +1 armor can use their bonus action to change its appearance, making it appear as any other armor, or as any set of clothes, as long as it covers the same parts of the body as the original armor. This effect is not an illusion, and the armor retains all of its capabilities and durability.
  • Mercurial armor requires a bonus action to don, no matter what type of armor it is
  • Shifting Form. When your form is altered (as via Polymorph or Shapechange, you can make your Mercurial Armor adjust to your new form, giving it the benefits as if it was wearing this armor as well. If you don’t, your new form’s natural AC is still increased by +1. 
  • Shapeless Armor (Recharge 5-6). When you are hit by an attack dealing slashing, piercing or bludgeoning damage, you can use your reaction to partly turn the mercurial armor and your covered body into amorphous mercury, reducing the damage by 1d8.
• Mercurial Ring. If a creature is wearing this ring and touches a different ring or seal with it, they can use their bonus action to transform it into a perfect ordinary non-magical copy of that ring or seal.
  • Once per 24 hours, you can also make the copy gain all magical effects and properties of the original, but they cannot be recharged. 
  • Poisoned Sigil. Mercurial Ring has 2 charges. While wearing it, you can expend 1 charge and use your action to touch an item or a surface and create an invisible magical sigil on it. The next creature that touches the item or touches the surface within 5 ft. of the sigil within the next minute must make a DC 15 Constitution saving throw. On a failure they become affected by the effects of the Confusion spell for 1 minute; a Short-Term Madness for 1 hour; or a random Long-Term Madness for 24 Hours on a failure, depending on your choice. Mercurial Ring regains 1 charge daily at dawn. 
• Mercurial Pole. A creature wielding this pole can use their action to change the pole’s length from anything between 10 ft. to 60 ft.
  • As an action, the Mercurial Pole can also be made thinner and flexible, giving it the properties of a 120 ft. rope that cannot be damaged by non-magical means. Changing it back into a pole requires an action.
  • As an action, the Mercurial pole can also be made into a magical Portable Ram giving a +8 bonus to checks instead of +4. Changing it back into a pole requires an action.
  • (Recharge 5-6). The Mercurial Pole can be used like a +1 magical Quarterstaff for a single attack, but with the reach of 60 ft.

Tongs of Thousand Forms have 5 charges. You can use your action to touch a Mercurial item with the tongs and expend a charge to make the item Mercurial indefinitely. You can also expend 2 charges to turn any viable Non-Mercurial item into an indefinite Mercurial item. 
The charges can only be regained by touching an item made indefinite by this feature and using your action to remove its Mercurial property. 

Losing attunement makes all items lose the Mercurial property.