The Ace of Spades

Weapon (dagger), Very Rare

Playing for the high one, dancing with the devil, Going with the flow, it’s all a game to me

This magical dagger is a favorite among gamblers. When wielding this dagger, your weapon attacks with it score a critical hit on a roll of a 19 or 20. Additionally, while the dagger is on your person, it cannot be found by nonmagical means against your will.

Curse: This weapon is cursed, and sometimes seems to have a mind of its own. When you roll a 1 on the d20 when making an attack with this weapon, it strikes you instead of the intended target. This hit counts as a critical hit.

Creator's Notes Obviously it is most useful to rogues because the smaller damage die of a dagger is less impactful when you've got Sneak Attack damage, but I can also see a monk using it.

When I was working on it I was informed that Sneak Attack (and I assume Martial Arts dice) are not automatically applied to the attacks if you meet the conditions for them. Because of this, I recommend if you use this item make a decision on what happens on a 1 with a player with that sort of ability.