On the Four Types of Damage in Original D&D
Sort of a short observation today. What follows are all of the spells in the Original D&D Little Brown Books that can cause direct and specific points of damage:
Fire Ball: A missile which springs from the finger of the Magic-User. It explodes with a burst radius of 2" (slightly larger than specified in CHAINMAIL). In a confined space the Fire Ball will generally conform to the shape of the space (elongate or whatever). The damage caused by the missile will be in proportion to the level of its user. A 6th level Magic-User throws a 6-die missile, a 7th a 7-die missile, and so on. (Note that Fire Balls from Scrolls (see Volume II) and Wand are 6-die missiles and those from Staves are 8-die missiles. Duration: 1 turn. Range: 24"That's actually it. Some things that I didn't count here: Spells that kill outright (cloudkill, death spell, disintegrate, finger of death). Spells that summon a monster to fight on your behalf (conjure elemental, invisible stalker, sticks to snakes, animal growth). Spells that come later in Supplement I (magic missile, ice storm, prismatic wall, blade barrier, etc.) Phantasmal forces, because it has no specific amount of damage indicated and is otherwise troublesome ("Damage caused to viewers of a Phantasmal Force will be real if the illusion is believed to be real").
Lightning Bolt: Utterance of this spell generates a lightning bolt 6" long and up to 3/4" wide. If the space is not long enough to allow its full extension, the missile will double back to attain 6", possibly striking its creator. It is otherwise similar to a Fire Ball, but as stated in CHAINMAIL the head of the missile may never extend beyond the 24" range.
Wall of Fire: The spell will create a wall of fire which lasts until the Magic-User no longer concentrates to maintain it. The fire wall is opaque. It prevents creatures with under four hit dice from entering/passing through. Undead will take two dice of damage (2-12) and other creatures one die (1-6) when break ing through the fire. The shape of the wall can be either a plane of up to 6" width and 2" in height, or it can be cast in a circle of 3" diameter and 2" in height. Range: 6".
Wall of Ice: A spell to create a wall of ice six inches thick, in dimensions like that of a Wall of Fire. It negates the effects of creatures employing fire and/or fire spells. It may be broken through by creatures with four or more hit dice, with damage equal to one die (1-6) for non-fire employing creatures and double that for fire-users. Range: 12"
So by OD&D Vol-1, there's only four ways that you can deal damage to someone -- magic fire, cold, lightning, and mundane weapons. And this explains why a lot of the monsters have those 4 things specifically called out, for example (from Vol-2):
OCHRE JELLY: The clean-up crew includes Ochre Jelly and similar weird monsters. Ochre Jelly is a giant amoeba which can be killed by fire or cold, but hits by weaponry or lightening [sic] bolts will merely make them into several smaller Ochre Jellies...While to modern eyes those may looks like a rather odd and motley assortment of things to call attention to in each case (fire, cold, lightning, and weapons) -- especially in later works like the AD&D Monster Manual -- in OD&D in makes a lot more sense, as it's simply a comprehensive treatment of every damage type that exists in the game. (Compare also to the table for Dragons with respect to their receiving different damage types.)
BLACK (or GRAY) PUDDING: Another member of the clean-up crew and nuisance monster, Black Puddings are not affected by cold. It is spread into smaller ones by chops or lightening bolts, but is killed by fire...
GREEN SLIME: A non-mobile hazard, Green Slime can be killed by fire or cold, but it is not affected by lightening bolts or striking by weapons...
A couple more observations that we can make from this -- OD&D is actually fairly low in the "wahoo" scale, most spells being fairly subtle in effect, and quite compatible with classic swords & sorcery literature. The four spells above are the "flashiest" things in the game, elements that I sometimes wish weren't there for flavor sake, and yet even those have clear analogs in Conan stories (e.g., fireball, wall of fire; see here). After that, we might say that it's fairly obvious and even lazy game design to thereafter add more spells that just do alternate methods of damage output. When you later add something like magic missile with its untyped damage, then you wind up either in an ambiguous situation with regard to the monsters above, or else a cheesy short-circuiting of the game rules, depending on your perspective.