Lockshiv

Weapon (dagger), uncommon
  This mundane bladed syringe holds a lead-heavy concoction that inhibits a creature’s ability to interact with the Weave. With intricate mechanics, the injection mechanism can be pre-loaded, allowing the weapon to release its magic-inhibiting effects when thrown.
  When you hit a creature with this weapon, it must succeed on a DC 13 Constitution saving throw or be unable to concentrate on spells until the end of its next turn. In addition, if it tries to cast a spell before the end of its next turn, it must make a DC 13 check using its spellcasting ability modifier. On a failure, it expends the spellcasting action but does not expend the spell slot. On a success, it casts the spell as normal.