Viper Whip

You can conjure a venomous whip lined with a deadly stinger at the tip.  This weapon lasts until the spell ends.  This counts as a light one-handed melee finesse weapon with a reach of 10ft that you are proficient with.  Upon a hit, it deals 2d4 piercing damage.  If the target is a creature, it must succeed a Constitution saving throw equal to your spell save DC.  On a failed save, it takes 2d6 poison damage and is poisoned until the end of its next turn.  On a successful, creatures take half damage and is not poisoned.

At Higher Levels.  When you cast this spell using a spell slot of 3rd or higher, the poison damage increases by 2d6 for every two slot levels above the 2nd.