#sludge form

This Transformation type Quirk activates whenever the user comes into contact with someone. The user can then transform their body into a purple slime with a set of eyes and mouth. The user then covers the target and starts to puppet them, forcing their control over the target's motor functions and leaving them unable to act unless the user moves them. The user can move around the target and control specific body parts if they wish. If the user touches anyone in this state, they can jump bodies or spread their control to others, though they can only have one true host that their main body is attached to. When the user returns to normal, all of their slimely parts return to them, freeing any of their targets. This gives the user a dangerous tool, able to turn their enemies bodies against them. They can make enemies fight on their behalf, hold people hostage, hide themselves on another person, leave enemies open to attack, or just use it to piggyback off people to get around. Though the user can be removed from the target, especially through immense physical strain like damage to the user or pulling the user off the person. Spreading themselves out will weaken the user's control over the targets. The Quirk only targets the targets the target's motor functions, so they can't access someone's memories or the like.

This Transformation type Quirk allows the user to take on a large mass of green slime in a humanoid shape. This form is rather large, being twenty five feet tall. This enhances the user's strength and durability, especially making them far more resilient to kinetic attacks. The user has a minor control over their body while in this state. They can try to stretch themselves out to grab something, try to compact their body to make them even denser, or wrap part of their body around something they touch. This mixed with the user's density can potentially let the user capture others in their body. This gives the user an amazing Quirk for defense, able to tank whatever the world tries to throw at them. They can bulldoze their way through attacks, trap enemies inside their body, smash their way through defenses, pull in allies to protect them from harm, or just belly flop on top of their enemies to hurt them. Though major damage could force the user out of the form, seemingly getting launched out of it. Trying to morph their body will make them more vulnerable to attacks. The user's size can be an issue, such as accidently getting objects or people caught in them or just making them a massive target.

Realistically, Muscular has a big advantage. He was able to handle a fully powered Izuku, whose attacks could very well blast Sludge Villain apart. However, Sludge Villain could try to take over his body. If anything, the extra muscle padding should make it easier to take Muscular over, letting Sludge Villain slink into his body without him noticing and potentially even controlling the extra muscles. He also doesn't have any counters to the possession. Unless he can flex so hard that he explodes Sludge Villain out of his body, there's not much he can do. Especially since Muscular may be one of the dumbest fighters in this entire series. I could easily see him beating up Sludge Villain, thinking he got him, and then immediately getting taken over afterwards. Now, is this a likely outcome? Who knows. I'll just say that Sludge Villains Wins. Because to me, the mental image of Muscular beating himself up is too good to pass up.

So while full power "Decay" is pretty strong, there are a handful of ways to counter it, or at least slow it down or circumvent it. The first is through breaking up the spread. By destroying whatever it's spread it through or moving it into the air, such as when Pixie Bob burrowing through the ground to stop it's spread. Other large scale manipulation powers could do that same, like "Whirlwind" or "Cement". By that same metric, just destroying whatever is being hit by it could stop the spread as well, such as with "Black Hole" or "Overhaul". For more direct attacks, there are powers that can block it by preventing direct contact, such as Snatch being made up of a bunch of sand particles. This could extend to "Sludge Form" and "Flight" as well. Finally, powers that can heal the user could work as well as long as they remove it, such as with "Lizard Tail Splitter" or "Super Regeneration" cutting it off before it spreads.

Obviously, having any other Quirk will be a detriment since it would shorten the lifespan of whomever has it. That being said, I think that any Mutant ability would interact with "One For All". To a degree, at least. I do think that they could help cushion some of the training needed to work "One For All". At least ones that enhance the body, like "Dupli Arms" or "Frog". By extension, "One For All" could enhance their abilities with "Tail" I don't think they'd work with anything that isn't purely augmenting the body, though. Like it wouldn't interact with something like "High Spec" or "Sludge Form". As for anything that grants more out there changes like "Sludge Form", I believe that anyone could still use their Quirk from something like that. Then again, using "One For All" may just end up blowing your arm off whenever you try to use it. You could still put it back together, but it's going to be annoying trying to exercise even more caution with how they use the explosive power.

This Mutant type Quirk alters the user's body, giving them a gray, rocky-like form similar to concrete. This form is tougher than normal, but seemingly doesn't have any defineable traits. The user can choose to soften themselves to become like wet concrete, giving them greater flexibility and mobility. This flexibility allows for greater control over themselves, letting them reform and shape themselves and harden it. This can mold the concrete in any number of simple shapes, like growing spikes around their body or moving it around to a certain point to protect themselves. The user can be selective with this, like changing the hands into hammers and leaving their forearms pliable, letting them smash them into foes like wrecking balls. This gives the user a versatile power, with their unique form having equal parts power and flexibility. They can adapt around their foes, turn themselves into weapons, crawl their way through tight spaces, use their rocky form to protect themselves, or just make little sculptures. Though the user will need to soften themselves to reshape and can spread themselves out to far, leaving them far more vulnerable to losing parts of their body. The user will need to focus in order to shape themselves.

It's a coin flip for Shinso and Momo. Sludge Villian could win against them, but it depends a lot on his personality and whatever Momo can cook up to try and counter the sludge body. The same goes with Tokoyami. I think it'd be pretty hard to get around Dark Shadow, but I doubt Dark Shadow could put out the damage to really to Sludge Villain down, effectively stalemating. We know that Mina is a hard counter to him and could easily win, though she may not go that far in a setting like this. Denki, Shoto, and Izuku are all pretty certain victories, shocking him unconscious, freezing him in ice, or simply blowing him to pieces again.

This Emitter type Quirk allows the user to make a gelatinous substance from their mouth. This substance will then turn into replicas of the user, making up to twelve in total. The user has a general understanding of the current condition and movement of their copies. The user can shift and combine these clones together into a greater myriad of shapes like clay. This can come in a variety of forms, like extending out limbs or sprouting out wings to fly around. This makes the clones quite resilient, with the user being able to heal them back into place if they wish, and make more if they are lost. The user can combine these clones together to give them a greater amount of resources for a single target. This gives the user a versatile ability, allowing them to make ever-shifting and swarming squadrons. They can adjust their copies as the situation calls for it, shift them all into a giant form to battle others, augment their copies with new appendages, augment their copies with various parts, or simply have them around to help out the user. However, the further these clones deviate from the user's original form, the less cohesive and stable they are. This makes them weaker and more difficult to maintain, especially if the user tries to fix them or bring them back together.