The Rabid Heavy is a ferocious monster who is a terror in close combat, I'm making this guide out of inspiration from an amazing video, he deserves the credit for the idea behind the Rabid Heavy, all I'm doing is integrating it into a subclass!
Saxton Hale bless you Crash Maul!

The Rabid Heavy is a scary subclass if used right, its main threats are spies and snipers. The Rabid Heavy is also not a class that you can play alone, it appreciates company! You will namely need the Cowboy Engy (talked about later in the guide), afterall, without its master the Rabid Heavy doesn't know what to do! You'll also benefit from a pocket medic, so grab one of those too!

As a monster who does melee damage, you won't really be using the miniguns to fight with, you aren't smart enough, besides, you won't need the minigun anyway. Though there IS one minigun that I personally think will be helpful: the Huo-Long Heater! With this, you can channel your primal rage into a physical tangible form, the form of fire! This can mostly help for crowd control and spy checking, but never EVER fire a single bullet, otherwise you won't be a rabid heavy anymore, use the ammo only for the flame effect!

For your secondary, you're gonna be using the Buffalo Steak Sandvich, the food of the beast, pure undiluted meat! With this item you give yourself minicrits and a speed boost, but you lose the ability to use your minigun, which isn't much of a problem anyway since you don't use your minigun to begin with! With the minicrit boost and speed boost you will become a faster, stronger killer! Make sure you know when and when not to use it however, as you also become more vulnerable to damage...

For your melee weapon, you're obviously gonna be using the Warrior's Spirit, also known as the Bear Claws. The Warrior's Spirit increases melee damage while also healing you when you score a kill! However, it also makes you more vulnerable to damage, so be wary...

Cosmetics are the most important part of this class, it'll separate you from all the other heavies! For the first cosmetic you'll either want the Bear Necessities or the K-9 Mane. If you wanna look like Crash Maul's iconic Rabid Heavy you should go for the K-9 Mane, but the Bear Necessities gives you the look of a wild monster as well, so it's ultimately up to personal preference! Unfortunately the glowing red eyes and pale skin are rather hard to replicate... closest you can get is using a voodoo soul, but that's a holiday restricted item... and it leaves a huge hole in your gut! Ultimately the other two cosmetic slots are optional, you can leave them empty, you can use a voodoo soul to partially replicate the original Rabid Heavy, or you can put your own spin on it! I personally recommend that you go for cosmetics that emphasize your monstrous nature!

Next we'll be talking about the Rabid Heavy's master, the Cowboy Engy! The Cowboy Engy's main priority is supporting the Rabid Heavy by protecting him from threats that he can't deal with on his own by causing distractions with sentries, as well as placing dispensers in places where the Rabid Heavy can access them. The Cowboy Engy may take a bit of time to master and it requires a good bit of teamwork!

The Cowboy Engy's primary is never really elaborated on, though he most likely uses an old fashioned shotgun, going by the Cowboy theme, so it probably wouldn't be a bad idea to go with that! The widowmaker could also be viable, given metal will mostly go towards supporting the Rabid Heavy anyway, and as long as your aim is true (and since your a Cowboy, it should ALWAYS be true) you'll have unlimited shots! The panic attack could also be potentially viable...

Unfortunately it's impossible to give the Engy a revolver in game, but you can get pretty damn close! The lugermorph is a great substitute! I'm sure Max won't mind you borrowin' it pardner! If you don't have the lugermorph you can also just use the stock pistol...

Your melee weapon is also up to the imagination, as the Cowboy Engy portrayed by Crash is never seen using a melee weapon, other than his bare hands, which is currently not possible in TF2... fear not! There are still options! Personally I prefer to use the Gunslinger, as it's the closest you can get to bare handed combat, and the minisentries are good distractions to support your Rabid Heavy! If that's not your thing you can also go for the Stock Wrench, the Jag could also work thanks to its faster construction speed!

Like the Rabid Heavy, Cosmetics are very important for the Cowboy Engy. You will need to make him look like a Cowboy (duh!) so you'll need the Texas Ten Gallon, a classic cowboy hat! Another good cosmetic item is the Wild West Waistcoat, and you can also use the Texas Half-Pants and the Support Spurs, sadly using everything at once is impossible so which ones you use and don't use are ultimately up to you, but you must at least have the hat!

This is a bit of a gameplay addition, there were no medics helping the Rabid Heavy in the video, but this ain't the video. If possible, two pocket medics are recommended, one for the Cowboy Engy and one for the Rabid Heavy. The Rabid Heavy's pocket should be using either the stock medigun or the Vaccinator. The Kritzkrieg is not recommended for the Rabid Heavy as the Rabid Heavy is pretty good with damage output on its own, instead the pocket medic should be focusing on bolstering the Rabid Heavy's poor defenses, the stock ubercharge grants invulnerability, which can be horrifying to the enemy team, and the Vaccinator helps compensate for the Rabid Heavy's damage vulnerability. The Cowboy Engy will benefit from a kritz medic to boost his damage output.

The Rabid Heavy works best as an ambush hunter due to its slow speed, a Disciplinary Action Soldier could potentially fix this, but I doubt many people have enough friends for that much cooperation (or at least I don't). When paired with a medic the Rabid Heavy can become much more effective with head on charges, and he'll benefit from the Cowboy Engy distracting key threats to the Rabid Heavy while also providing a dispencer when possible. The Huo-Long Heater can help with Spy Checking and inducing burn damage on gangs. The Cowboy Engy should focus on eliminating threats such as snipers and, if possible, spies, as well as preventing other enemy team members from ganging up on their Rabid Heavy through use of distractions such as sentries/minisentries. The pocket medic should focus on compensating for the Rabid Heavy's damage vulnerability using either the stock medigun or Vaccinator, and if there's an extra pocket medic, that medic should pocket the Cowboy Engy with a Kritzkrieg, as the Cowboy Engy will have to kill threats before they can kill him or his pet!

Overall, the Rabid Heavy and Cowboy Engy require teamwork in order to be effective and can be very tricky to master, but once you got a team together you can potentially become a devastating force!

That's about all I have to say pardners, have fun experimenting with this, and thanks for reading!