billd91
Not your screen monkey (he/him)
Well, OK, but then what is the dividing line between 'mass' and 'regular' melee? I don't really see those terms used in any consistent way, the word 'mass' or 'mass combat' seems to crop up now and then, but I don't get the impression Gygax is saying there are clear categories of combats. Truthfully, in all my years of AD&D play (20+) I never saw a DM insist on attacks vs random opponents, unless there was some reason like they all looked identical. Even then such things were rare enough that I'm not sure it ever happened. Monster attacks were sometimes randomized by DMs, probably more out of a sense of running monsters with limited intellect in a fair way than anything else (IE the giant spiders are INT 1 and really don't know to target the wizard).
I suspect the wizard making an attack roll is an editorial thing. That or Gygax interpreted the description of Shocking Grasp to require a to-hit. Knowing how Gygax ran games that wouldn't surprise me at all!
Editorial? I don't think so. Magical touch attacks are mentioned under Melee Combat in the Player's Handbook on page 104. And the random target issue is under Who Attacks Whom on page 70 of the DMG.