Source: The Book of Many Things

Weapon (war pick), very rare (requires attunement)

You gain a +1 bonus to attack and damage rolls made with this magic war pick. It has the following special properties:

Meld into Stone. You can cast the Meld into Stone spell from this war pick. Once this property is used, it can’t be used again until the next dawn.

Petrification. The war pick has 1d6 + 1 charges. If you score a critical hit against a creature that has fewer than 100 hit points, you can expend 1 charge from the war pick to have that creature make a DC 15 Constitution saving throw. On a failed save, the creature has the petrified condition for 8 hours. When the war pick has no charges remaining, it loses this property.