Your weapon imparts a disease that cripples your foe as you strike them.

The first time you hit with a melee weapon attack during this spell's duration, the attack deals an extra 2d8 Poison damage to the target.

Additionally, if the target is a creature, it must make a Constitution saving throw, potentially becoming

Poisoned

Diseased

Critical Success (+10). The target is unaffected.
Success. The target is Poisoned until the end of its next turn, and the spell ends.
Failure. The target is Poisoned for the duration of the spell. While it is Poisoned, it is also Diseased.
Critical Failure (–10). As failure, except if a creature was affected by Disease, its highest ability score is reduced by 1d4 until it completes a long rest.

At Higher Levels: Increase the damage by 1d8 for each spell level increase.