Source: Tal'Dorei Campaign Setting Reborn

Weapon (hand crossbow), very rare (requires attunement)

This strange contraption of gears, wires, and lacquered wood has a handle with a metal grip and crank. Its stock bears a flamboyant maker’s mark that reads: “Made in Hupperdook,” a city in Wildemount. You gain a +1 bonus to attack and damage rolls made with this magic weapon.

When you roll a 20 on an attack roll made with this weapon, you can immediately make another attack with this weapon after resolving the critical hit. When you roll a 1 on an attack roll made with this weapon, you must succeed on a DC 14 Dexterity saving throw or take 1d6 piercing damage as some of its gears and wires spring loose.