I'm back with another post, just to assure everyone that I'm not taking another year-long hiatus. I've also changed up the format slightly, to make the statistical changes less awkward to write about. (I may even figure out how to format it properly by the next post.) Let's have at it!
Rocs first appeared in OD&D Vol. 2. Superficially they are still the same monster (a Bloody Big Bird), but there are some changes that alter it in significant ways. Probably the biggest is a change in demeanor. The original Rocs were more likely to attack Chaotic creatures and be friendly towards Lawful types. Now Rocs are Neutral in alignment and have an animal intelligence. They really are just big birds now, and further away from the Tolkienesque eagles they resembled before.
OD&D also has notes about the likelihood that young Rocs will be found in a nest, but here that has been dispensed with in favour of a terse note about their nests containing the treasure of former victims. Young Rocs were previously able to be trained, but that's also been omitted. Instead we learn that Rocs are tamed and used by giants. Perhaps the giant thing is a recent development? It could serve to explain the change in their nature: as the giants prey on them and train them, so they become more hostile and animalistic.
It also fits with the stat changes noted below. The steep drop in Number Appearing indicates that they've been hunted extensively by giants. The Hit Dice totals listed below are deceptive. In OD&D, a 6 Hit Dice Roc was standard, but the possibility for larger types with double or triple Hit Dice was given. In the Monster Manual, only the full 18 Hit Dice variety is listed. Again, it indicates to me that the giants have hunted out the smaller varieties.
Stat changes: Old: New:
Number Appearing: 1-20 1-2
Move: 6/48 3/30
Hit Dice: 6 18
Damage: 4-16/4-24 3-18/4-24
Ropers first appeared in The Strategic Review #2, and like most of the monsters Gary created for the magazines he hasn't revised it much at all. It's still the same weird creature, with strength-draining tentacles, immunity to lightning, resistance to cold, and a weakness against fire. And an 80% magic resistance, to top things off. It still has a gizzard that contains treasure, but the gem count has been dropped from 20-50 to 5-20, and they've picked up a taste for platinum. (Treasure-gizzards are awesome.) In OD&D, characters hit by the Roper got a save vs. poison to avoid the strength drain. In the Monster Manual, it seems that is no longer the case. They've also lost their immunity to Charm spells. And their alignment has changed from Chaotic to Chaotic Evil (as per Strategic Review #6).
Stat changes: None
It's the dreaded rot grub, making its first ever appearance in D&D! They're normal-sized grubs that live in offal and dung, and are appropriately weak. But if any character touches one, it will burrow into their flesh and kill them in 1-3 turns, unless fire or a cure disease spell are applied to the victim immediately. Presumably this was Gary's home-grown deterrent for PCs who spend their time searching every nook and cranny of the dungeon. Hey, you want to stick your hand in a pile of shit looking for treasure? Good luck with that.