Coolmint Slice

Weapon (dagger or scimitar), uncommon (requires attunement)
  This striped, blue blade is enchanted with the power of the elemental coolmint. You have a +1 bonus to attack and damage rolls made with this magic weapon.
  Decorate. While holding this weapon, you can use your action to conjure a torrent of sticky, white and purple sugar as you cast the cone of frosting spell (save DC 13). Once you use this feature, you can’t do so again until the following dawn.
  Magic Item Set. Attuning to both this weapon and the peppermint slice requires only a single attunement slot. If you hit a creature with both of these weapons on the same turn, the weapons become empowered until the end of your next turn. This weapon deals an additional 1d4 cold damage and the peppermint slice deals an additional 1d4 fire damage.
  Rare variant: Your bonus increases to + 2, the magic item set damage increases to 1d6, and cone of frosting is cast at 3rd level (save DC 15).
  Very rare variant: Your bonus increases to + 3, the magic item set damage increases to 1d8, replace cone of frosting with cone of cold (save DC 16).