Wondrous Item, rare (requires attunement by a requires attunement by a spellcaster )
Once per turn while wearing this bangle, you can deal an extra 3d6 damage to one creature you hit with a spell attack if you have advantage on the attack roll.
The damage is of a type dealt by the spell attack. If you're a rogue, you can choose for the amount of extra damage you deal to be equal to your Sneak Attack damage instead; you can still only deal Sneak Attack damage once per turn. If a spell would allow you to attack multiple times over the course of its duration, this extra damage can only be dealt on the turn the spell is cast.
In addition, you can ignore the verbal component required for any enchantment or illusion spell you cast while you're in total darkness and wearing the bangle.
Notes: requires attunement by a spellcaster