Ironthorn Javelin
Ironthorn Javelin
Weapon (javelin), rare
This javelin has no special effect until its command word is spoken, at which point it begins to hum with energy. Once it is activated, you can use your action to throw it at a creature you can see within 120 feet. The target must succeed on a Dexterity saving throw against a DC of 10 + your proficiency bonus + your Strength or Dexterity modifier (whichever is higher) or take 50 piercing damage. The target gains no benefit from nonmagical cover on its saving throw. Whether the target succeeds or fails, the javelin is destroyed after being used in this manner.
Ref: TPKB1 p87