Well.. showdown and its silly automatic IV changes...
Okay in response to Elly, I shall explain my pokemans.
I built this team to utilize smeargle in its ability to be overly predictable. Most, if not all of the smeargles run hazards, spore, and destiny bond which leaves opponents shrugging off smeargle as just a hazard setter. So I made it as a lead trick room setter. With magic coat, smeargle can prevent common taunt leads, such as liepard, mismagius, and archeops from preventing smeargle from setting trick room, fights opposing smeargles, and now and then I can get a free hazard up from slower pokemon such as sandslash which might not go for earthquake. As for dark void's use, it prevents my opponent from blocking my sleep move by simply having a grass type, a vullaby, and various sap sipper pokemon such as miltank, and sliggoo. Essentially wasting my opponents turn, and getting a free sleep status, and limiting what pokemon I have to watch for sleep blocking, such as Xatu, magmortar, and primeape. It makes my decision making a whole lot easier. Parting shot lets me swap out to an appropriate sweeper, while also minimizing damage to them if my opponent happens to wake up. What I have noticed many times, the team generally falls apart if I make a mistake with smeargle.
Mesprit was made as a bulky trick room setter for the purpose of, like smeargle, setting trick room, and pivoting to an appropriate sweeper. Unlike smeargle however, I tried to make mesprit bulky enough to be able to take multiple hits, and to work as a check to priority moves, the most common being mach, and bullet punch(Sucker punch can be avoided by not using U-turn) aswell as be able to not die from most attacks from either attacking type. Overal mesprit has been good to the team, allowing me to keep up pressure with swaps, and protect the rest of the team, while keeping weaknesses to a minimum.
Aggron is a horrific beast when given a choice band. From what I have noticed, headsmash, and heavy slam destroy the entire tier. The only things that give these 2 moves problems are steelix, ferroseed, torterra, physically defensive gastrodon, and opposing aggron. Low kick does consistent damage to steelix, and enemy aggron without dropping my attack, and in the case of a sturdy steelix or sturdy aggron, super power lowering my defense isn't a fun thing to have happening. Unfortunately, my last moveslot is stuck between chosing to hit torterra, or ferroseed. I chose fire punch for the ferroseed. The negative speed nature on aggron is to prevent enemy steelix and aggrons from outspeeding, or speed tying my aggron. All in all, Aggron forces out many things that my 2 stab moves mostly 2hko, especially headsmash which 2hko's many things which resist rock.
Camerupt, oh man do I love camerupt. The choice specs eruption (even after 1 stealth rock switch) is amazing. You can't even begin to laugh at a specs eruption from this guy. From my experience with camerupt, the only things I have to deal with is hariyama, vibrava, mantine, and air balloon ninetales (not very prevalent mind you). Camerupt deals with torterra, and gastrodon is 1hko'd via hidden power grass, if it is a physically defensive set, freeing aggron from any sticky situations. Together, camurupt and aggron's horrendous strength cover each other really well, which is why I decided to pair them together for my trick room core. Now, one problem I have faced between these 2 is barrier, calm mind musharna which relies on moonlight (although aggron checks it pretty hard, its still a problem).
Now this is where the tricky parts have come in. The final 2 pokemon have seen many drastic changes. From a malamar, to a mega Audino, and so far these 2 have given me the most success.
Abomasnow glues the team together perfectly. Being able to take care of any type of defensive pokemon with max attack and special attack, as well as bringing hail to stop musharna from being able to heal and breaking the sturdy/focus sashes of many pokemon, Abomasnow softens up pretty much all team cores I have found, as well as hurting both camerupt, and aggron's more prevelant checks and counters with its great movepool. While hariyama can stop abomasnow's blizzards, it can not stop a wood hammer. Hariyama's bullet punch also cannot directly knock out abomasnow, leaving hariyama no options. Vibrava is not even an issue, gastrodon gets wood hammered, magmortar which may be used to take a blizzard or woodhammer cannot defend from an earthquake. Abomasnow is truely terrifying, and I have found no reason to replace it. You might however.
Finally, we are now down to the one pokemon I always have doubts with.
Beheeyem is one of the pokemon that scream trick room. However, I find it difficult to use. While it functions as an offensive trick room setter, I find that it just cannot survive any hits to set up a trick room. Although if it does manage a trick room, it takes out malamar easily. I'm finding it really hard to do anything with beheeyem honestly, besides its not bulky enough, and the limited turns of trick room restrict my use of calm mind, or nasty plot, which it originally had in place of trick room. Although, before it had trick room my team did have a harder time keeping trick room active, as too much stress was put on mesprit and smeargle. Beheeyem, in my experience isn't really necessary to the team in the slightest. I have tried faster pokemon such as scarf primeape, and choice specs swellow in beheeyem's place, but they haven't contributed to the team either as they commonly get left by themselves with trick room still up. :L
This is how my team functions. The average game lasts around 10 turns and 3 trick room set ups, as I run this similarly to a weather team, where the only thing I have to worry about is keeping my field condition in place. All in all this is a good team. Its one of the best I've made during my almost 3 years of constant NU play. I just don't know how to make it better. Stealth rock isn't a problem, hazards don't worry me too much as my sweepers output too much damage and end battles fast enough for chip damage to not matter unless I play against a dedicated hazard stacking team with ferroseed, garbodor, and smeargle or something. I do agree on the dark weakness being an issue however, but I attribute that to beheeyem, which oddly enough is the thing that hits dark types with super effective damage lol.
Also, I hope you enjoyed my light novel. If there is anyhting you'd liek more clarity on I'll answer it the best I can. :L