OK Now What

FuzzyGeff pointed out something he'd noticed about AD&D a long while ago.

Violet fungus does: "The excretion from these branches rots flesh in but one melee round unless a saving throw versus poison is made or a cure disease is used."

That's all well and good, but what is the game effect of that?

Here is the complete quote from both the Player's Handbook and Dungeon Master's Guide:

"                                                                                             "

Yup, nada.

Although the DMG calls the attack "rotting poison" and under poisons on page 20 it says,

"The poison of monsters, regardless of its pluses or minuses to the victim’s saving throw, is an all-or-nothing affair. That is, either they do no damage, or they kill the victim within a minute or so. Poison potions generally do the same, although you may optionally elect to have any given one be slow-acting, so that the victim will notice nothing for 1-10 hours after quaffing it."

Surely they fixed this for second edition, right?

"The excretion from these branches rots flesh in one round unless a successful saving throw vs. poison is rolled or a cure disease spell is used."

What do the rules say?

Nada.  But there are rules for "rotting touch" from a mummy.

4th edition doesn't appear to even HAVE violet fungus.

5th edition says, "Multiattack. The fungus makes 1d4 Rotting Touch attacks.  Rotting Touch. Melee Weapon Attack: +2 to hit, reach 10ft., one creature. Hit: 4 (1d8) necrotic damage.

Now we're getting somplace!

What's necrotic damage?

The 5e Player's Handbook says, "Necrotic. Necrotic damage. dealt by certain undead and a spell such as chill touch. withers matter and even the soul."

Damage is damage in 5th edition, unless you're immune to a type; then it's harmless.