Blight

The target must make a CON saving throw and takes 8d8 {b} or ½ on a success.

Undead or Construct takes no damage.
Plant Creature or Magical Plant has disadvantage on saving throw, max damage.
Plant makes no saving throw, it simply withers and dies.

{x}: 1d8 {b} per level.

“I drain their vitality, spreading decay through their veins like a spreading rot.”