Venomous Plague

 You pour the venom on your hand and say the incantation and shoot a ray from the same hand at one target in range, when the ray reaches the target it takes the form of the creature the venom used in the spells conjuration belongs to and attempts to bite the target.

Target makes a Dexterity saving throw against your spellcasting DC.
On a successful save the ray shoots harmlessly past them. On a failed save, the target takes 1d6 poison damage and is poisoned for 5d4 turns.
While poisoned by this spell a creature takes 1d6 poison damage at the end of each of their turns. They then make a Constitution Saving Throw DC 15.
On a successful save reduce the turns they are affected by this poison by 1. On a failed save, the effects of the poison continue as normal. If a creature fails the saving throw 3 times, extend the duration by 1d4.
A creature effected by this spell can have it cast on them again. On a successful save the ray passes them harmlessly. On a failed save, extend the condition by an additional 5d4 tuns and if the creature has been effected by this spell before, they now make any Constitution saving throws against the poison effect of this spell at disadvantage.
If a creature makes it to the end of the duration of the poisoned effect caused by this spell, they immediately expel the contents of their stomach and are stunned and prone for the next turn and cannot take reactions the turn this effect ends.

The poisoned effect of this spell can be treated like any normal poison.

Using a Higher-Level Spell Slot. The number of creatures you can shoot the ray at increases by 1 for each level above 5th this spell is cast at.