Rod of the Prism-Grasper

Rod, rare (requires attunement by a spellcaster)

This ten-inch metal rod has a flared tip that resembles a torch's protective cage, or a spiky crown. At its bottom end are what resemble tiny metal claws surrounding an indentation. It seems it could hold something small there.

As an action, a creature attuned to this Rod may insert a magical gemstone into its indentation, where the metal claws come to life and hold it in place. Only one gem may be slotted into the weapon at a time.

While this Rod holds a magical gemstone, you may choose to transform it into a shortsword of rainbow light. Different gemstones will alter this appearance and provide alternate forms, and you may switch between these forms by using your bonus action. As part of that same bonus action, you may magically alter the weapon's balance, granting it the Finesse property. If you do so, reduce the size of the damage dice for that form by one step.

``2d6 -> 2d4 -> 2d2

``1d12 -> 1d10 -> 1d8 -> 1d6 -> 1d4`

Whatever its form, you are considered proficient with this weapon while attuned to it, and you may use your spellcasting modifier for attack and damage rolls in place of Strength or Dexterity. Additionally, this weapon is considered a +1 weapon, and it deals magical damage of a type determined by its inserted gemstone.

This Rod has 2 charges that may be used while a gemstone is slotted into it. You may spend 1 charge to cast the Faerie Fire spell.

Depending on the gemstone inserted into this Rod, it also gains additional properties. Most commonly, these Rods are accompanied by at least one Elemental Gem.
This Rod regains all charges at dawn.

Effects by Gem

Elemental Gem (Emerald)

While slotted with an Elemental Emerald, this rod's weapon form deals cold damage. It appears as though made of swirling water, coral, and algae, and it may take on the form of a Whip that deals 1d6 damage instead of the normal 1d4. Additionally, you may use 1 charge to draw upon the Emerald's power to cast the Torrent spell at 1st level. You can spend 2 charges to cast the spell at 2nd level.

Brimstone of Accelerated Decay

While slotted with a Brimstone of Accelerated Decay, this rod's weapon form deals split damage: its damage dice deals fire damage, while any modifiers deal necrotic damage. It appears as though made of sickly yellow sulphur crystals of varying opacity with veins of flame that run through them, and it may take on the form of a Longsword that is shaped like a Khopesh. Additionally, you may use 1 charge to draw upon the Brimstone's power to cast the Inflict Wounds spell at 1st level. You can spend 2 charges to cast the spell with a range of 30 feet.

Ruby Sending Stone

While slotted with a Ruby Sending Stone, this rod's weapon form deals psychic damage. It appears as though made of semi-translucent burgundy crystal with an inner glow, and it may take on the form of a morningstar that deals 2d4 damage instead of the normal 1d8. Additionally, you may use 1 charge to draw upon the Ruby's power to cast the Dissonant Whispers spell at 1st level. You can spend 2 charges instead to cast the spell at 2nd level.

Greater Sending Stone

While slotted with a Greater Sending Stone, this rod's weapon form deals psychic damage. It appears as though made of a core of stone covered in semi-translucent crystals of varying colors and opacities, all with an inner glow, and it may take on the form of a maul. Additionally, you may use 1 charge to draw upon the Stone's power to cast the Wrathful Smite spell at 1st level. You can spend 2 charges instead to cast the spell at 2nd level.

50% Pure Filocite

While slotted 50% Pure Filocite, this rod's weapon form deals force damage. It appears as though made of solid strands of purple-blue light, and it may take the form of a Spear. Additionally, you may use 1 charge to draw upon the Filocite's power and cast Detect Magic at 1st level. You may spend 2 charges instead to cast the spell Identify.