Caustic Blade

As part of the action used to cast this spell, you must make a melee attack with a weapon against one creature within the spell's range, otherwise the spell fails. Your weapon grows rows of tiny teeth that secrete a vile caustic liquid. On a hit, the target suffers the attack's normal effects, and it is coated in a pungent acid. At the start of the targets turn it takes acid damage equal to your spellcasting ability modifier and the spell ends.

This spell's damage increases when you reach higher levels. At 5th level, the melee attack deals an extra 2d4 acid damage to the target, and the damage the target takes at the start of its turn increases to 1d4 + your spellcasting ability modifier. Both damage rolls increase by 2d4 and 1d4 respectively at 11th level and 17th level.