Burning Poison

With your weapon coated with poison you infuse it with fire magic to deliver a more effective strike. 

the poison retains its potency for 1 minute or until you hit with the weapon or ammunition. When a creature takes damage from the coated weapon or ammunition, that creature must succeed on a DC 14 Constitution saving throw or take 2d8 poison damage and become poisoned until the end of your next turn.

Additionally, the creature will take 2d4 fire damage (When using higher level spell slot, the fire damage increases by 1d4)