To editors; try to avoid putting in too much first-person text, it's a guide not a rant.
This is a decent set of guidelines for how to make GMod Monsters. Note that these are not concrete rules, just a handy set of guides made to hopefully dissuade the would-be Sue author. Monsters that existed and were documented before this list was made (older than Oct. 10, 2011) get a free pass because they've stuck around this long and people like them.
1: Give it a reason to be a Monster at all. Edit
Perhaps the most obvious thing is that a Freak or Monster without abilities might as well not be a Freak/Monster at all. Make sure there's some kind of special abilities at work. Psychic powers, fire-breathing, flight, troll-flailing, the power to point at randomness itself, etc. - If it's going to be a monster, it needs some kind of special ability, be it physical or supernatural.
2: Know your limits. Edit
Generally a monster can have as many abilities as its creator sees fit, but too much power or too many abilities eventually comes to a point where the monster with them is boring and no fun to see around. The same goes for ones that are blatant attempts to become the strongest ever. This ties into:
3: The Killer Cake LimitEdit
Painis Vagicake and Fadkiller are the most powerful and always will be, and to be frank only the latter is confirmed as such; they represent the strongest Monsters can become, period. This is called the "Killer Cake Limit", a theoretical limit on Monster power before it becomes too much.
While not officially accepted among the GMod community and better seen as a filter than an actual cap, trying to surpass it will not be taken well. Something as powerful or more powerful than them is likely only going to get made fun of and your creation comically humiliated in all its appearances, or will just end up seeing it disregarded or shunned, due in no small part to the sheer amount of power you've tried to give them. So much power in one freak is basically an obvious display of creator power fantasy, and that's just a cringeworthy display for all involved. Many badly-made freaks have attempted to go above this limit, most have ended up shot down; And that's just in the cases of ones that weren't outrageous Sues. Frankly, even Vagicake is in shaky standing due to the nebulous nature of GMod freaks and its status as a mishmash freak. This rule also goes hand in hand with the next:
4. Give your monster some kind of weakness or flaw!Edit
This should be obvious. An undefeatable monster is a bad one, because introducing it anywhere will mean everything except it is doomed, and that's no fun at all. This is the same kind of general rule that should work for all fictional characters of any kind: A character without flaws is unbelievable, boring to use or watch, and generally is looked down on; Monsters are no exception. This can be bypassed if the character or Monster is very well-written/characterized, but the chances of it not making the cut are dangerously high. Give some way to get the advantage over your monster; Their weakness doesn't have to be simple to figure out or use, but any weakness is better than none whatsoever.
Try to be original!Edit
We try to encourage creativity around here, so show some. Doing something like copying Painis Cupcake's abilities into a Scout, or copying Christian Brutal Sniper into an Undertale character? That isn't creative; that's derivative, and on an unbelievable scale. On top of that, this kind of "copy one monster into a new body for a new monster" behavior has been done so many times it's pathetic. If a monster can be summed up as "X monster, only as Y", get rid of it. Given a few traits to make it unique when shown alongside its original (or supposedly original) counterpart (Ass Pancakes and SoupCock, FlutterCook and Assnick) will make it okay, but don't simply copy one monster into a new body and give it a few tiny details in an attempt to set it apart. And on the note of "X monster, only as Y,"
5. Avoid making copycat or mix-and-match pony freaks. SERIOUSLY.Edit
This is a recent, but major problem. Over the past two years since this guideline set was last updated, there has been an exponential rise in the number of pony Monsters. These are, 99% of the time, weak rehashes of existing Monsters into pony form, or a mix-and-match of character/Monster abilities and personality traits into a cheap pony shell. Characters like these are, again 99% of the time, terribly designed or have no reason to exist. Not everything has to have a pony equivalent, MLP fandom. Stop it.
The same goes for copying freaks into Undertale characters (like someone will make an AU called "Underfreak"), Sonic characters (Sonicbine is the example of mix-and-match), etc.. The source work doesn't matter, the fact that you copied X into Y without doing anything else is the important part to be avoiding. BEARPENlS is the example of a mix-and-match animatronic. Don't make your own monsters to look like this, or they can also turn into bad examples for other people like this.
6. If you make a backstory, make sure it isn't contradictory.Edit
We have seen this happen plenty of times before and we promptly suggest to follow this bit. If there's a backstory at all, make sure it pieces together in a way someone can understand. This rule, of course, only applies to Monsters that are given a defined backstory, and hence this rule can be disregarded if your Monster has no solid pre-appearance history.
7. Make sure there exist videos, and that they don't degrade the quality of the monster they present.Edit
The Pumpkin Lord-O-Lantern is a great example for terrible Monster, terrible videos. When this guide was made, it had only a single video, and the frame-rate is so slow it's almost impossible to get what's going on. Do not do this. It paints you and your monster in a bad light. Get some decent video editing software, audio too if possible, and then watch some existing GMod - preferably that which is regarded as particularly valuable to the community - and figure out what they did right.
Get a video editor you feel comfortable with, learn some stopmotion, Fraps and sentence-mixing, and do better than the example shown, at the very least.
8. Make the Monster easy to pick up. Edit
All of the most popular Freaks have a good story-line or catchy name or just something that makes them more recognizable than the random rabble that many try and fail to establish. This is why Painis Cupcake, Christian Brutal Sniper, and Vagineer are so well-known compared to other monsters.
This doesn't mean nonsense doesn't have its place. Some of the best GMOD work out there is nothing but the video's creator throwing things out to see what happens. It's just sometimes random isn't the right technique, especially if implementing it into how a Monster operates. If they have some form of cohesive gimmick, they're easier to remember.
Revision Line. Don't just assume things will be canon just because you say they are!Edit
Another recent issue over the past while. This affects existing Monsters just as heavily as it effects newer ones; don't add in relationships to an existing Monster as tight-knit as relatives or marriage partners without it being accepted by the creator of the Monster in question and/or by the general populace. The latter generally requires a video be made to be done with any degree of success. Just because you want it to be true doesn't mean that it is. Without qualifiers, your statements of relation mean nothing, and trying to repeatedly keep your personal canon in place on the pages of the Monsters in question will just draw increasing ire from the admins who have to fix what you broke. There is a separate wiki for Fanon you should use for the ones that don't have a video planned instead.