Snakes and weapons go hand in hand, as far back into antiquity as Moses throwing his staff to the ground and it turning into a deadly viper. (I am something of a Biblical scholar and know that isn't quite how it's described, but stay with me.) Even going back to Adam and Eve, where snakes were featured as being great deceivers being eloquent with their tongues. The Bible also says in Proverbs that words can be used to cut as much as heal.
But I digress. We're talking about swords, not words, but there's only one letter of difference between the two. Perhaps the two could be used together...
I give you the Serpent's Rapier. A weapon truly meant for sinister charlatans and word-wise bards. The rapier is a sword known for its slenderness, but what a lot of people don't realize is the blade is as heavy as a longsword and just as long, to boot. The thing is, you don't notice the weight as much when the blade is in hand due to the balance of the blade. Longsword are tip heavy compared to rapiers.
So, what makes this blade so unique? Looking at the basket, as the rapier is a basket-hilted weapon, you can plainly see a snake entwining itself around the handle. The blade itself is engraved with a serpent going down half the length of the sword, with the fanged mouth halfway up the sword.
Of course, such weapons would not be sought without game-altering effects. The weapon has a +1 bonus (as all magic weapons should) and grants a +2 bonus to Persuasion and any other skill that someone would use in order to charm, influence, or otherwise gain the favor of those who listen and understand.
If you like the idea, let me know what you think.