The Missingno (No, really, it's serious. PEACH)

[Kazyan]

That would definitely work - good idea.

EDIT: I had an idea for CongealRefine's no-error effect (or for its own thing) that might fit a bit better into the "battlefield control" slot that the error-part has: Expanding a five-foot square into a ten-foot square. On a gridmap, you'd do this by subdividing the square into quarters. It seemed to fit with the whole unusual-effects theme, it's a space-distortion so it fit with the error effect, etc.

That idea is much better than what I threw together; editing in now.

[Qwertystop]

That idea is much better than what I threw together; editing in now.

A note: It's not just moving - straight-line ranges have to go through the whole thing, area-effects measured as distance-from-point (anything with length or radius) get distorted...

EDIT:
Pre-playtest info (that is, character-building): It's very MAD. I rolled very well (17, 15, 15, 14, 13, 12), but... I need two good ones in Dex and Int to be able to use Exploits, and I need Str and Con to actually deal and take damage - using a Finesse weapon means either rubbish damage or burning a feat on Weapon Proficiency: Rapier (and still having low damage), unless I want to just stay in one State forever for proficiency.

Also, the only [Glitch] feats that you can take before level 6 are Favored Exploit and Momentary Awareness. The former feels really underwhelming (though that might just be my admittedly-poor sense for how much one error matters), while the later requires that after you've put your best four stats in Str, Dex, Con, and Int, you still have a 15 left over for Wis.

Also also, there's a couple relics in the feat list, and possibly elsewhere: mentions of a "glitchiness level" and "Knowledge (Glitch)." At least one of the former was typoed as "glithiness."

[Kazyan]

Qwertystop poked me over PM to bring this thread back up, because he has some more balance concerns and commentary. Lazily bumping now.

[Qwertystop]

Thanks for that.

So, firstly:

I did that Exploit reformat we'd talked about. I also added a little summary to go above and explain the general mechanic. I did my best not to modify anything mechanically, but there are a couple of places where it was unclear or odd where I did my best to clear them up (for example, the duration of immunity for making a Will save against ReachBypass, and the range of the same).
Missingno writeup - new:
All Exploits have a normal effect (denoted below with a 0) and an Error Effect (denoted with a number). The normal effect is either an always-on passive ability or an ability that can be used at will. The Error Effect is used by taking on the number of errors preceding the description. Many Exploits also have augments (denoted with a + before the number). These improve the Error Effect in some way (they do not apply to the normal effect). An augment is used by taking on an additional number of errors above the normal cost of the Error Effect, as listed before its description. Augments are not paid for separately - if an Exploit has multiple augments, the Missingno can use any or all augments with a cost less than or equal to the amount of additional errors taken in using the Exploit. For example, if a Missingno were to take six errors in using ConspireInform, they would be able to send a verbal message silently as a swift action (base Exploit, 1 error), of up to 150 words (25 words base, plus 125 words from the +1 augment five times over), to anyone within a mile (+5 augment).
Some Exploits have the same name as a lower-grade Exploit, with a single + appended. These do not have their own normal effects - they add additional augments to the lower-grade Exploit with which they share a name (or the base one, in the case of chains of + Exploits such as AccelerateAct). A + Exploit cannot be learned without knowing all previous Exploits (those with the same name, but less plusses).

Least Exploits

Spoiler

Show

AccelerateAct
0: Target a weapon. While it is on your person, you can draw it as a swift action as a teleportation effect.
1: Full-round action: teleport to any point adjacent to an enemy within 10' and make a single melee attack. If necessary, draw a weapon mid-teleport.
+4: Target is treated as flat-footed against that attack.

ChangeOrient
0: Move-action: Stand from prone without provoking an attack of opportunity, as a teleportation effect.
1: Make a creature within 10' either prone or standing (choose one) as a teleportation effect. Will negates.
+1 Increase the range by 5'. This augment can be added multiple times.

ConspireInform
0: Swift action: Deliver a secret message of up to 25 words within some other speech, as per the Bluff skill but without making a Bluff check. Unintended recipients can make a Sense Motive check to understand the secret message.
1: Swift action: As above, with no detectable communication required (speech, gestures, etc.). Unintended recipients thus cannot make a Sense Motive check to intercept the message. The intended recipients hear the message as though you had said it normally, but know it's not normal speech. They do not hear the message if outside of hearing range of you.
+1: Increase the maximum message length by 25 words. This augment can be added multiple times.
+5: The message can be heard by any intended recipients within one mile of you.
+9: The message can be heard by any intended recipients within 100 miles of you, and each recipient can give a 25 word response that you hear.

EditEquip
0: Can make cosmetic changes to any weapons held or armor or shields worn. This does not apply to natural weapons or armor, or unarmed strikes, leaves modified equipment in the same general shape and size (for example, a longsword character cannot be made to look like a hammer or enlarged or shrunk enough to count as a different handedness). This produces no mechanical changes, with one exception. Armor that has to be specifically fitted to a character, such as full plate, can be fitted to you by this as long as it is for a creature of your size category and general body shape (humanoid, quadruped, etc). When no longer held or worn, the weapon, armor, or shield returns to normal.
1: Can change a weapon into another weapon of the same handedness and damage type (slashing/piercing/bludgeoning), a shield into another shield for the same size creature, and armor to different armor of the same general composition (metal, leather, wood, etc.), type (light/medium/heavy), and size. This has no visible effects - changing Splint Plate into Full Plate results in Splint Plate that has the exact stats of Full Plate. The normal (no-error) effect of EditEquip can be used to make the appearance match up with the reality (or make the two even more separated). All changes still revert when the item is no longer held or worn.
+2: A weapon's damage type or an armor's type can be changed (Greatsword into Greatclub, Chain Shirt into Full Plate).
+4: A weapon's handedness or an armor's composition can be changed (Dagger into Lance, Studded Leather into Chain Shirt).
+8: An item's size can be changed, up to Colossal.
+12: An item can be made into a special material (adamantine, alchemical silver, etc.
+16: Weapon and armor templates can be applied, nonmasterwork items can becom masterwork.

ExpressBlur
0: Touched writing becomes unreadable, though still visibly text. This is a mind-effecting illusion effect. You may also revert this with another touch.
1: Immediate action: Reroll a saving throw against a language-dependent effect, with a +1 insight bonus on the reroll. You must take the new result, even if it is worse.
+2: Increase the insight bonus by 1, and you may allow one ally (not yourself) within 120' their own reroll, with the same insight bonus. This augment can be added multiple times.
+10: You automatically succed on the saving throw (your allies do not, but they still get the bonus you would get).

MeltFreeze
0: Freeze or melt up to 1 gallon of water touched.
1: Change the hardness of an unattended object touched by 1. The object behaves as a material with its new hardness (selected by you). If reduced below zero, an object becomes liquid, and behaves as your choice of nonhazardous (to typical humanoids) liquid. If a liquid's hardness is raised above zero (unmodified, a liquid has hardness -1 for this purpose only), it becomes solid, and behaves as your choice of solid with its new hardness. Multiple applications of this ability in the same direction (increase/decrease) do not stack (the most extreme change, relative to the original hardness of the object, is the only one to remain). Multiple applications in opposite directions negate each other point-for-point. This is an instantaneous effect (it does not expire).
For example, a piece of leather (hardness 2) with hardness decreased 3, it might act as water, being liquid, safe to drink, and freezing and boiling at the same points (though it would still look like leather, especially when still). If the leather's hardness was instead increased by 6, it could behave as stone, being brittle and absorbing heat well. If these two changes were made to the same piece of leather (decreased by three, then increased by six, or vice versa), it would have hardness 5, and act as wood, being flammable and slightly flexible.
+1: Change hardness by an additional 1. This augment can be added multiple times.

ReachBypass
0: Full-round action: teleport an object you can hold in one hand to you. If it is within 30', it appears in your hand, or at your feet if your hands are full (if it is not, this action fails). If it is attended, the attendor can make a Will save to negate; if they succeed, this exploit fails when used on any object attended by them for the next 24 hours.
[b]1:[b] Full-round action: Same as above, but the object can be anything you can hold in up to two hands.
+2: The object can be up to 120' away.

RemoveExist
0: As an unarmed touch attack, inflict 1 point of damage on a creature or object. For this damage, the creature or object's Damage Reduction and hardness is treated as 7 lower (minimum 0).
1: As an unarmed touch attack, inflict 1d6 points of damage against a creature or object, bypassing all Damage Reduction and hardness. The damage is also not made nonlethal by Regeneration.
+3: Increase the damage by 1d6. This augment can be taken multiple times.

ReverseFall
0: Immediate action: You can use Feather Fall on yourself only, except that your falling speed immediately becomes 150' per round and you take 1d6 falling damage when you land.
1: Immediate action: When falling at least 10 feet, instantly appear at the bottom of the fall, prone, taking no falling damage, as a teleportation effect. In situations where you would normally never hit bottom (bottomless pits, in orbit, etc.), this Exploit fails.
+4: Instead of appearing at the bottom, appear at the top, where you were before you began to fall. If this place is no longer occupiable (if it was destroyed, is now occupied by someone or something else, etc.), this fails.

Haven't gotten to the non-Least yet, I've been working on my own class.

Second:
Dexterity-based weapon-users usually have a lot of trouble getting damage to scale. Either they take three feats (or a Swordsage dip and one feat) to get Shadow Blade for Dex to damage, or they have some other class ability that gives them bonus damage (Skirmish, Sneak Attack, maneuvers, etc.). This class has no such class abilities - while Exploits and States are all either utility-granting boosts to melee fighting (closing gaps quickly, impairing enemies, safety from trip AOOs) or unrelated non-combat utility, nothing actually gives you bonus damage, which means you can't actually do much to hurt people, no matter how good you are at getting to them safely and with good gear. States are similar, giving defenses, utility, or mobility. The exceptions (RemoveExist, TossCompress, and SpectralFlippant) don't work well with any of the rest of what you do, and aren't enough on their own. RemoveExist is implausible for more than a few hits a day to get enough damage to be effective, since it's an unarmed touch attack, unless you're only a secondary Missingno and a primary something-that-works-well-with-unarmed-attacks-or-natural-weapons. TossCompress is similar - doing meaningful damage for 16th level and up at 1d4 per error takes a lot of errors, it's mostly for the utility of pinning people or for shredding large groups of not-really-a-threat. SpectralFlippant is similar - it's a reasonable chunk, but not enough unless you've got some way of forcing people to move through it, which means you're spending your turns running rings around enemies and provoking AOOs - and not doing much if you can't get behind the enemy and Bull Rush.

And if you're not being Dexterity-based, you're really MAD, because you've got to keep Strength up in addition to Dexterity, Intelligence, and Constitution.

Third:
This is a lot more minor, but I think the first half of your Epic feat (the bit that lets you ignore mundane obstructions like locks) could really just be a State, possibly attached to an AC bonus when flat-footed (what you don't know can't hurt/stop you). Perhaps limited to locks that have a DC below some scaling-with-level number - class level plus ten, perhaps, a little lower than what a Rogue with no Dexterity modifier could get taking ten. I mean, it's basically Knock at-will, except you can't actually get anyone else through so you have to stick around. Doesn't feel big enough for Epic.

[Kazyan]

Since people seemed to like this class and I dropped the ball on giving it the attention it deserved, so I went back today and gave it a tune-up. Hopefully things should be clearer now, and the nomenclature should be finalized--"exploiter level" now replaces "error level". Some smaller things have been added, and some glaring editing mistakes are gone.