Vines acid whip

You create a magic whip which you can wield and become proficient in this weapon, being able to add your ability to cast spells at the time of attack instead of your strength, the whip remains in in your hand for the duration of the spell or when you release it. the whip does 2d6 of acid damage, the enemy must make a Constitution saving throw, if it fails it takes an extra 1d4 acid damage and his AC is reduced by 1 (this effect is not stackable)

At Higher Levels. When you cast this spell using a spell slot of 2rd level or higher, the damage increases by 1d6 and 1d4 for every two slot levels above 2nd. At level 5 of your character the AC is reduced by 2