This is the first time I found out about this secret. There is cauldron in last room of Laboratory with named lich and many eyes. If you use the cauldron, your character dies. Apparently, if character is cursed, he gets 50 Intellect permanently instead, and he can use it multiple times until his Intellect reaches 255. You can do it for your whole party.

I heard about this as rumor, and conveniently I had Lloyd's Beacon in Mire of the Damned. So I flied there to get mass cursed by local Harpy Witches and returned back to Laboratory. Screenshot of room with cauldron attached.

Edit: one of characters is drunk instead of cursed, that's because of common Harpy's attack.

Swords of Xeen has an easily repeatable event that raises the Personality of a Cleric or Paladin (possibly Druid/Ranger as well?) permanently and can be abused to raise it to 255.

Then again, Swords of Xeen also has a fountain that gives the character 200 HP and *doesn't check to see if your HP is already above its maximum*. This means that HP overflow is possible.

In Darkside of Xeen, if you go to Sandcaster, cast Time Distortion, face south, and wait until noon, everyone will gain 1800 SP. This can be done once per day and again doesn't seem to have a limit, so SP overflow may be possible here.

In MM2, you can get over 65k HP with Max HP potions, as long as you don't rest. (Note that leveing up may cause your current max HP to overflow.)

Unlike in previous MMs, you don't need to go that much out of your way to get 255 Int in MM6. Also in MM6+ your stats can go well above 255, though you get last bonus at 500. Absolute maximum value for stat, when it is still useful, is 5000, because when your characters are very old and have 90% stat penalty, 10% of 5000 is exactly 500 :)

Also unlike previous MMs, you have periodic stat boosters in MM6 - it includes pilgrimage and barrels/cauldrons/bones/etc. in dungeons.

You also can get more than 65k HP/SP with high enough levels. Problems arise when you start dealing with negative numbers for training cost, you can still pay that much gold, but game has its own rules on math operations with negative numbers...

There seem to be many of this type of easter egg secrets, but this one is really taking it far. I wonder why none of the game designers ever made a comprehensive list.

Because MM6 became like science. Did you know, for example, that MM6 has 11 (!) unfinished dungeons which were dummied but still exist in game files? :))

Did you know that Wizardry 8 (the game I am playing now) has a fair number of unobtainable items, including multiple gadgets and the Thermal Pineapple?

MM6 also has 17 unobtainable items. But what is obtainable is far more interesting :) I always felt that MM item system was superior to that one of Wizardries - it features affixes, many equipment slots, etc.

On other side, MM 6 has more unfinished dungeons than there were finished dungeons in Wizardry 8... And even smaller dungeons, like Agar's Laboratory, are larger than those in Wizardry 8... When are you planning to give MM 6 a go?:)

That happens in a lot of games. Baldur's Gate has a lot of unused stuff too, that was later cut out from the game.
But MM6-8 has lots of those extremely weird "do action x to get an unexpected result" eastery egg secrets. I know other games have it as well, but MM6-8 seem to take it to the extreme, and for other games it usually becomes well known within a few years after the game's release at most.

When I got upset that my 50/50/.../50 Wiz8 characters had nearly same damage output as level 1, and I couldn't find good upgrades for them in-game, I decided to use editor to give them some better gear and I found nothing worth noting at all. However, each time I am finding chest in any MM game, I always feel excited, because even gold is far more useful than what I remember in Wiz8. Gadgets is more like Wizardry 8's gimmick. Just like blasters are gimmick of MM 6. In all the honesty, I'd rather have blasters :)) What concerns crafting side, MM 6 features Alchemy, which features much more recipes than Wizardry 8's Alchemy and gadget-making taken together :) Did you play Xeen on "Adventurer" mode? "Warrior" mode uses true unaltered combat formulas, and AC, just like Accuracy, become very important. Resistances were protecting against magic attacks. Getting HP below -10 isn't supposed to be commonly accepted occurrence, just like dying and losing in general.

In contrast, in Wizardry there is also only physical AC, which barely gets effected by anything, and you don't have much control over resistances either. Character scaling in Wizardry 8 is especially bad, but I already mentioned it before. Enemies in MM6 can have 2 kinds of attacks + special effect. MM7 added 1 more attack and improved turn-based combat, sadly it was much weaker in some other game aspects than MM6. However, if MM6 had movement in turn-based mode, like in MM7, it would beat Wizardry 8 in absolutely all aspects. Wiz8 would grind to a halt in fights like fight with Snergle in his mines, or Temple of Baa's "gong" fight. Those two fights alone probably have more monsters than Wizardry 8 has as a whole.

There are plenty of uses for items in Wizardry 8, *especially* if you have a Bishop, as nearly every spell of 5th level or lower is available in a buyable spellbook. In addition, there are other very nice items for sale:

Crook (in the swamp) sells:
Stiletto (Dagger, usable in the offhand, with 10% Kill)
Amulet of Healing (+3 AC, +1 HP regen, 5 charges of Heal All (power 6) which is useful before you learn the spell, and can be sold to Lord Braffit for a recharge)
Amulet of Life (4 charges of Resurrection and is cheaper than buying Resurrection Powder, but requires 35 Artifacts)
Thieves' Buckler and Ankh of Speed both boost Speed +10 points each

Sadok (in Marten's Bluff) sells:
Stun Rod (Polearm with 9-23 damage, 20% paralyze, +10 Polearms)

Bela sells some nice Ankhs and a +20 Strength accessory for at least one of the two stamina casters

Then there is Ferro, who sells lots of high end equipment such as Infinity Helms, Robes of Rejuvenation, and The Mauler (IIRC, and this also has a good KO chance and 2% Kill), along with 5th level spells and powerful ammo with high Paralyze chances. (There is, of course, the small matter of getting enough gold to buy everything you want from him, as well as reaching him in the first place.)

So yes, Wizardry 8 has plenty of stuff to spend your money on.

(This is just the buyable items; there are some excellent non-buyable items like the Staff of Doom (Death Cloud) and the Diamond Eyes (powerful off-hand mace with high Paralyze chance).)

Spellbooks are also available in MM6 as well as scrolls.

What concerns other items, for each one I can name you 10 such items in MM 6. And unlike Wizardry 8, MM6 doesn't have stuff like "Loot Sensor".

Uses for gold in MM6 - spellbooks (though you can randomly find them in dungeons or from monsters), expertizing/mastering skills, shop services, travel services, training, Gold->Exp fountain, etc.

It is sad that you don't give MM6 a go based on some strange principles. I'd strongly advice you to check it (and without using various wikis and guides (and exploits) during first playthrough). This game is capable of changing your vision on how CRPGs can work

One thing is that I just haven't yet felt like playing a modern Might and Magic game, and right now I just happen to feel like playing Wizardry 8.

By the way, are status ailments useful at all in the modern Might and Magic games (6 and onward)? In other words, are spells like Sleep and Paralyze useful at all? (They are in Wizardry 8.)

You can definitely paralyze monsters and turn them into stone. You can shrink them, and you can revive them from dead if you want to torture them more (and get bonus exp). However, this approach is much more effective when it is used by monsters. They can curse, poison, disease, stone, knock out, kill, eradicate, drain SP, etc. In any case, MM6 allows many inventive approaches.

Also, "modern" MM games are several years older than Wizardry VIII :) Which made Wizardry 8 even more of disappointment for me, as I have played them in their original time. MM7 was weaker than MM6, and MM8 was much weaker than MM7 and it was more like fan-made game, after MM8 I was SOO much looking toward Wizardry 8, but it happened to be only a small fraction of MM8's goodness and padded with most tedious combat I have ever seen with level scaling completely ruining it. Shame that it was like this, I really liked graphics and art style...

Lol. Literally yesterday I was pissed off after triggering Harpy Witches that cursed my entire party in "Mire of The Damned". Seems like there is some benefit to that :D

This game is chokefull of secrets to discover. That's why everytime when I start with new party in new Sorpigal there is this sense of great adventure waiting ahead.