The old Mordenkainen's Disjunction, 9th level (Mage's Disjunction now?) was the terror of every high level group I was in.
The enemy mage cast it, and ...
The fighter lost his plate armor +3, shield +3, long sword +5, girdle of giant strength, and 5 healing potions. He lost the Stoneskin and Infravision cast on him.
The cleric lost her armor +4, shield +1, mace of disruption, cloak of displacement, helm of telepathy, rod of resurrection (30 charges!) and all her prepared scrolls of healing and protection (against various things.) She also lost the effects of the Prayer and Bless spells she had put up, the mobile Protection from Evil, and the Negative Plane Protection as well.
The wizard lost his cloak of protection +5, his ring of protection +3, his staff of the magi (35 charges!), his wand of lightning, his rod of cancellation, and his talisman of the sphere. Also, his Stoneskin collapsed, along with his Haste, Fire Shield, one-way Wall of Force spell, Contingency spell, and that nifty Chromatic Blade spell (the blade it conjured disappeared.)
The thief lost ... (etc.)
All of this with no saving throw for any character, item, or spell effect allowed. Presto, and the entire party is permanently Demagicked!
Unless, of course, the party could cough up the money for about 5 or so Wishes to get all their items back, assuming they actually survived the battle with the Disjunction casting wizard ...
Oh yes, the party had an artifact/relic: the Ring of Gaax. The enemy wizard was 19th level, so his Disjunction had a 19% chance of taking out the Sword. And it DID take it out.
No Wish spell will ever get the Ring of Gaax back!
Back at that time, no Counterspell rule existed. One could not counterspell Mordenkainen's Disjunction, could not ready an action to counterspell, could not Reactive Counterspell (or whatever that's called), could not make observation checks in the 3E sense to see what was coming, and otherwise could not do much of anything.
The only thing you COULD do back then was appreciate it was an archmage you were facing, and HOPE TO GOD YOU WON INITIATIVE.
Yeah, it was a terror spell.
Edena_of_Neith