Backstabber's blade(a rogue's delight)

This little fiendish dagger is something my rogue loves. When you are in front of an enemy the only thing visible is the handle of a dagger. It appears completely harmless without an arcana check on it. But when the dagger is behind someone's back a shiny red blade appears from the handle. When put in someone's back side on top of the original damage(1d4+2) it causes them to bleed continuously for a set time (I set it at 1d4 per turn for a minute in combat) If the enemy dies by the stabbing or by bleeding out a red insignia that the killer choses is magically burned on the back of the neck as a calling card. You can scale damage however you like for your players but I wanted to make a dagger that a rogue would still feel good using at higher levels. This definitely helps my rogue play into their character.