DBD December Twitch Prime Reward

Actually this isnt the only artifact charm theres the epic games one you got if you got the game during that free period that was happening on epic

I think the Fogwhisperer-Charm and the Developer exclusive Entity-Charm are also Artifact rarity.
But rarity doesn't matter anymore I think since they give this charm and the golden Trickster Mask Artifact rarity even when so many people get these cosmetics.