One weapon in your possession becomes a Dragon Slayer or Giant Slayer (DM's choice) for the next 9 days. The Charm then vanishes from you, and the weapon returns to normal.
Charm of the Slayer
RewardXDMGp. 992024
Raw data
{
"name": "Charm of the Slayer",
"page": 99,
"type": "Charm",
"__prop": "reward",
"source": "XDMG",
"entries": [
"One weapon in your possession becomes a {@item Dragon Slayer|XDMG} or {@item Giant Slayer|XDMG} (DM's choice) for the next 9 days. The Charm then vanishes from you, and the weapon returns to normal."
]
}