I think there should be a poisoned weapon pack which includes:
1. Script which slowly damages you over time if hit by poisoned weapon. If you are already poisoned, you cannot be poisoned again to prevent abuse/crash/rape.
2. An antidote item which stops any poison you are infected with 1 time
3. A vaccine which protects you from poison damage on that life if used (also an immune player type)
4. Weapons such as poisoned claws (like fists, but poisoned), bow and arrows, spears, etc. Which deal normal damage and can poison
If you have ideas to make this idea better, please share them. Constructive criticism is accepted.
EDIT: Poison also slows the player down and turns his skin green.