Blood Blade

When you cast this spell you cut your body with the material component, Your hit point maximum decreases by 3 and the material component disappears. 

For the duration you can use your bonus action to draw a blade made of your on Bone, Blood and Sinew from your body. The blade is a magical weapon, uses your spell attack bonus when you attack with it and deals 1d6 Slashing damage on a hit. 

You are considered proficient with the Blade.

As a bonus action you can slide the Blade back into your body to conceal it, when the duration ends the incision in your body disappears, your hit point maximum is restored and the material component returns.