Chaos phage

Chaos phage was a magical disease most commonly inflicted by blue slaadi, a race of creatures originating from the plane of Limbo.

The disease was slow acting but incredibly fatal, and usually killed its host within days, causing them to rapidly wither away. People killed by the disease would be reborn as red slaadi. Spellcasters capable of casting more than basic spell would instead be reborn as green slaadi.

The disease could only be cured by magical means, and the transformation could only be undone by a wish spell.