The Rapier of Wit

One of the things video game RPGs do really well is weapon variety. In TTRPGs the vast majority of weapons are functionally identical. Your great ax does 1d12 damage, my great ax does 1d12 damage, everybody's great ax does 1d12 damage. Which is fine, of course, because you add your strength to that and maybe your proficiency, and then there's feats that might come into play. My point isn't that there isn't variety in TTRPGs, because there's tons. My point is simply that the variety is in the character you're building, not in the weapons they wield. 

And I'm not here to change that. Would it be kinda cool to have a book filled with unique weapons and every time your players buy or loot something they could roll a d1000 and see what they got? Sure. And honestly there's plenty of weapons tables out there that make a play at doing something like that; feel free to use those if you'd like. My experience, though is that a weapon carefully crafted to your narrative purpose will fit better in your TTRPG than some random +2 bardiche. Is the following weapon carefully crafted to your campaign? No. I crafted it for mine. But it might give you some ideas, and if it sounds fun, feel free to steal it wholesale.

And with that may I introduce The Rapier of Wit.

Like this, but wittier

It's a normal rapier, with normal rapier stats. But whoever you stab with it is going to involuntarily say the most clever, most scathing thing they have ever said to whoever they happen to be looking at. If they're staring off into space a bird out there somewhere is going to burst into flames from the insult. If they're looking at a character or a monster that person is going to make a Wisdom (or equivalent) saving throw against taking damage. If they save they'll take half damage. If they fail they'll take the full hit and have disadvantage on their next action.

In D&D specifically this looks an awful lot like Vicious Mockery on steroids. The creature stabbed must be able to speak at least one language. When stabbed they automatically use a reaction to let loose with a frankly awe-inspiring insult directed at a creature they're looking at within 60ft. If that creature can hear them it will make a DC15 Wisdom saving throw against 5d6 psychic damage and disadvantage on their next skill check, save, or attack roll. On a successful save they'll take half damage and avoid the disadvantage. Creatures that can't hear, for whatever reason, aren't affected.

A few notes on playing this weapon; if you're playing a more light-hearted game, consider not actually telling your players what this rapier does. Just describe an incredibly well-balanced and frankly quite gorgeous sword to whoever winds up with it and let them discover this detail themselves. It's also not necessary for you to actually craft the most clever insult of your life every time someone gets stabbed with this thing. Just describe the effects of the words as if the words themselves are in fact somehow dangerous to utter at the table. Though if you want the added challenge of saying the most clever thing of your life over every attack round, feel free.

Now at first blush this sounds like an incredibly stupid weapon. Sort of a two-edged sword where the sword edge you use to strike your enemy is blunted and the sword edge pointed at you is The Subtle Knife. But with a little creativity I think you'll be surprised what sorts of unique attack methods could arise in your game with this thing. If you can sneak attack a guard talking with their buddy, you might be able to get them to kill each other. Or maybe it makes more sense to stab your party's barbarian with no ranged attacks so he can take a shot at the harpy flying above you. Is it possible that your players will also accidentally kill each other with it?

Sure. But if there were no chance of catastrophic failure the game wouldn't be very interesting, now would it?