In calculating Basic D&D monster experience, what's a special ability?

Question

I really like my good ol' Moldvay Basic D&D. Every once in a while, it's missing a rule I want, and I make it up. Then I feel clever. Sometimes, though, I want to know what everybody else did or does. Like now:

Moldvay, B22, gives a table for determining monster experience point value. You find the base value for the monster's HD along with a per-special-ability bonus. Then the answer is simple:

XP Value = BaseXP + (#Abilities * AbilityBonus)

No definition of "special ability" is provided, but monster blocks include an asterisk for each special ability to be counted. For example, the carrion crawler (B32) has a given HD of "3 + 1 *" implying that its total XP value should be 75: 50 + 25, for one special ability. Presumably its special ability is its ability to paralyze.

Mentzer's Basic (at least the set that I have) lists the computed XP values, and it agrees: 75 XP.

In Labyrinth Lord, the carcass scavenger (p67) is a monster basically identical to the carrion crawler. The LL rules don't give per-special-ability asterisks, but do precompute XP. It's worth 135 XP, which would be 65 + 2*35, implying two special abilities, using the XP table on p49.

My copy of the AD&D 1E Monster Manual doesn't give a special ability count or a computed XP.

The reason I find the count of special abilities interesting, especially in this case, is that the carrion crawler has a brutal eight attacks per round. Then again, they don't do damage, they paralyze. Then again, once the party is paralyzed, the crawler will eat them whole.

How are special abilities generally counted? Do extra attacks count? Surely an orc with eight attacks is vastly more difficult to defeat than one with four, and so on. Do weaknesses detract from the expected value? (The shoggoth in LL ROCC is a 7 HD 1590 XP monster, implying 3.286 special abilities, if I've done my math right)

I'm interested in a good rule of thumb, and especially interested in documentation of common rules actually used "officially."

Answer 1

Moldvay is great... in part because it's short. Tom and I spoke at some length about the 'tack' he would take. I later used a lot of ideas that he omitted because he just didn't have room. The following will address the BECMI treatment, being the most detailed expansion of Moldvay's data. At this distance (almost 30 years), most players consider the two nearly equivalent. (With apologizes to the ardent and more discriminating fans of either edition...)

Special Abilities are defined in BECMI, and summarized in the Rules Compendium (RC). The majority are Special Attacks, which include:

Acid, Blindness, Charge, Charm, Continuous damage, Disease, Energy drain, Paralysis, Petrification, Poison, Spell ability (1 per 2 spell levels), Swallow, Swoop, Trample

Some Special Defenses (Immunity to normal weapons, Spell immunity) are also Special Abilities.

Although the carrion crawler merits only one Asterisk by-the-book (for Paralysis), the overview of 'btb' is important: all of the published details are Guidelines, not rules. The ultimate choice always rests with the gaming group. Feel free to assign it an extra asterisk if you wish.

A counter-argument would be that the small (2' long) tentacles, while formidible, can rarely be directed at more than one target... and while that's going on, everyone else can hit it easily (AC7, unlike the AC3 head in AD&D) and its magic avoidance is mediocre at best (saves as Fighter L2).

But at the bottom line, the difference is 25 XP (per asterisk for a 3+1 HD monster), divided among the party... call it 4-5 XP per person. imho, not worth arguing about. So err in the characters' favor.

FM (author of BECMI)

Answer 2

The most detailed answer I could find is on page 84 to 85 of AD&D 1st edition DM's Guide.

On Page 85 Gygax gives extensive examples of what he considers to be Special Abilities and what he considers Exceptional Abilities (a term not found in Basic D&D). While AD&D is not Basic D&D both have their original development in OD&D and I would consider it a useful guideline to apply to both versions.