Contagion

Your touch inflicts disease. Make a melee spell attack against a creature within your reach. On a hit, the target takes 10d8 Necrotic damage and is poisoned.

At the end of each of the poisoned target's turns, the target must make a Constitution saving throw. If the target succeeds on three of these saves, it is no longer poisoned, and the spell ends. If the target fails three of these saves, the target is no longer poisoned, but choose one of the diseases below. The target is subjected to the chosen disease for the spell's duration.

Whenever the target receives an effect that would end the Poisoned condition or remove the disease, the target must succeed on a Constitution saving throw, or the condition doesn't end on it.

Blinding Sickness. Pain grips the creature's mind, and its eyes turn milky white. The creature has disadvantage on Wisdom checks and Wisdom saving throws and is blinded.

Filth Fever. A raging fever sweeps through the creature's body. The creature has disadvantage on Strength checks, Strength saving throws, and attack rolls, and you also can't take a Bonus Action or a Reaction.

Flesh Rot. The creature's flesh decays. The creature has disadvantage on Charisma checks and Charisma saving throws and vulnerability to all damage.

Mindfire. The creature's mind becomes feverish. The creature has disadvantage on Intelligence checks and Intelligence saving throws, and the creature behaves as if under the effects of the confusion spell during combat.

Seizure. The creature is overcome with shaking. The creature has disadvantage on Dexterity checks, Dexterity saving throws, and attack rolls, and attacks have advantage against the creature.

Slimy Doom. The creature begins to bleed uncontrollably. The creature has disadvantage on Constitution checks and Constitution saving throws. In addition, whenever the creature takes damage, it is dazed until the end of its next turn.

At Higher Levels. When you cast this spell using a spell slot of 7th level or 8th level, the duration is 30 days. When you cast this spell using a spell slot of 9th level, the duration is instantaneous, and lasts until cured.