Viper Spit

As if from a snake-like creature, you spit out a deadly burning venom towards your target. Make a ranged spell attack against a target within range. On hit, the venom burns the target for 3d8 acid damage, the creature must succeed a constitution saving throw or take an additional 2d4 poison damage at the start of their turn for the next minute. They can repeat this save at the end of each of their turns, on a success the poison ends. 

At higher levels. When you cast this spell using a spell slot of 4th or higher, the damage of the acid increases by 1d8 and poison by 1d4 for each slot used above 3rd.