Toxicant Blade

When you cast this spell, you can choose a single dose of any kind of poison you are carrying (or any other potentially harmful substance that can coat a blade, such as holy water or a harmful potion) and that substance will magically coat your weapon, as part of the action used to cast this spell, you can make a melee attack with that weapon against one creature within the spell’s range. On a hit, the target suffers the attack’s normal effects and is afflicted with whatever poison or substance the weapon was coated with regardless of the weapon you used or if the substance or poison used is contact or injury based.

At 5th level, the attack you make with this spell deals an extra 1d8 poison damage. This damage increases by 1d8 at 11th level (2d8), and at 17th level (3d8).