You know I can't believe you say you did your research about Frillish in terms of the mons it counters (Samurott, Tauros, Hitmonchan, Primeape, Poliwrath??) and not mention some of the big threats it can fend off, like Barbaracle,
Pyroar, and
SpA Charizard. Fending off those two Fire-types in particular is helpful since Gastrodon, and indeed all but a handful of mons, cannot do so. I won't be opposed to
C- either.
With that said, competition with Gastrodon and Gourgeist-XL is pretty fierce, as they can handle a significant majority of what Frillish wants to counter. Frillish also suffers from severely diminished offensive presence, as its best method of damage output usually involves status and Night Shade (relying on a fixed damage attack for damage is never a good sign of your offensive presence), plus it has to keep a sharp eye on its health due to its lack of Leftovers, especially if hazards are present. These two drawbacks make Frillish rather easy to take advantage of.
Speaking of a mon that competes with Gastrodon...
I feel like Cradily has overstayed its welcome in C+. Gastrodon has taken Cradily's more notable niche in stopping the tier's Water-types, as not only does Gastro stop them more effectively / safely (not at risk of Ice Beam damage rolls / freezes or Kabutops's +2 / crit Stone Edge, can't be pivoted out of Lanturn's Volt Switch, not getting skewered by SD Samurott's Megahorn), but Gastrodon is much less vulnerable and more capable at fending for itself. This leaves Cradily's remaining niche as a Normal resist / Stealth Rocker with recovery. However, both those niches can be put into question by themselves. While Cradily can usually safely fend off Kangaskhan and Swellow, Iron Tail Tauros pretty much blows Cradily away, and it's not like the other Normal resists that are not as vulnerable to Iron Tail fold to Kanga and Swellow either. Meanwhile, SR + recovery is nice but is usually seen as an afterthought, and even then, Miltank could offer competition in that department while possessing more supportive options overall, having more diversity, and being vulnerable to fewer offensive threats.
To be honest, Cradily's Rock STAB alone reduces the amount of would-be offensive checks (Fire-, Ice-, & Bug-types), while also increasing the number of mons it can blanket-check / counter. However, Cradily suffers from two extremely notable flaws. The first is that it can barely do anything to mons that aren't threatened by Toxic or its STABs, as well as mons that can take it down quickly enough for Toxic to be a minor annoyance at worst. These usually include things like Poison-types, Steel-types, Fighting-types, and basically any setup sweeper that isn't hit for 4x SE damage; this is already a somewhat inherent problem when ur wall is taken advantage of by more mons than the amount of mons it claims to reliably wall. The other big flaw is that Cradily is used more as a blanket check to stuff rather than as a dedicated counter, due to the minimal amount of resists it has; this means that Cradily is often subject to narrowly avoiding 2HKOes from various SE coverage moves / unresisted STAB attacks, so Cradily detests being worn down even the slightest, despite what its bulk + reliable recovery may suggest. Simple offensive pressure (and sometimes even just Stealth Rock damage) can be enough to overwhelm Cradily as it is often be forced to decide between healing or maintaining any semblance of offensive presence, and of course status ailments greatly impede Cradily's job as well. Between the increased competition and its existing flaws, I feel
Cradily isn't worthy to remain in C+ anymore.
------Edit:--------------------------------------------------------------
Time to put the nail into this mon's coffin:
What reason even is there to use Muk these days? Things have gotten worse and worse for it as the days go by, and the amount of competition and answers to this have not gone down at all.
Right off the bat, this mon is pretty badly outclassed by offensive Garbodor. Offensive Garbo has a better Speed tier which gives it more flexibility and less need to predict, Seed Bomb which 2HKOes Omastar, Rhydon, and most importantly Gastrodon in one fell swoop, and consistent utility in Spikes + Aftermath so Garbodor doesn't have to do major damage or even remain healthy to contribute. Muk's only apparent benefits over Garbo would be Poison Touch and having Focus Punch, but Poison Touch only activates from Muk's weaker moves for only a 20% chance, while Focus Punch is a high-risk,
medium-to-high reward moves as it requires stellar prediction but doesn't manage to always OHKO its primary targets, so Muk gets forced out and still can't safely throw out a Gunk Shot later. If one wants to bring up Muk's superior special bulk in terms of checking certain threats, not only is Garbodor's bulk still comparable, but Skuntank practically checks everything Muk wants to and more.
Then we have the newcomers. Already talked about Gastrodon and how it's one of the hardest Muk counters by far, and is a fairly prevelant mon at that. And then we have Aggron, which is a definite competitor, if not usurper, for a Mega Audino answer that does utterly massive damage to everything, and threatens a lot more slower Pokemon overall. While Muk is not as vulnerable to special attacks, particularly offensive Mega Audino, the other aforementioned Poison-types can still answer Mega Audino while contributing far more against offense than Muk ever will.
Oh, you want to talk about Curse Muk? Alright, we'll talk about Curse Muk: it's worse than Curse Sliggoo, who only really demands Mega Audino be taken out of the picture, while Muk wants Ground-types, Steel-types, and
a lot more special attackers out of the way before it can work, and has far less utility than Sliggoo when not boosting. Even Vigoroth isn't near as demanding or, you know,
Arbok.
Muk just isn't specialized or even good enough to be in C Rank; it has rather low utility for a Poison-type (and especially poor utility for a mon as slow as it is), it's not even difficult to prepare for defensively compared to the other powerhouse mons that reside in C or even C-, and isn't a very respectable wincon either. Muk should definitely drop in Rank to C-, or preferably even
D / unranked :/
C- > D/Unranked: Golem isn't a bad pokemon per se, but the reasons it's ranked where it is (Sucker Punch + Sturdy Custap) are so situational most of the time that it becomes extremely difficult to justify using it over stuff like Rhydon and Steelix which offer far more consistency.
C- > D: Tail Glow pass is cool and all, but it comes at the cost of sacrificing a valuable teamslot for something that has very few setup opportunities, and can be deadweight against offensive teams in most cases. Volbeat also has virtually 0 bulk, and it's typing offers nothing to most offensive teams (since you wont be using this on Stall or Balance.) Overall, it's just a tad too gimmicky for a spot in C-, and I think D would be much more accurate of a ranking for Volbeat.
C- > D/Unranked: Vullaby was a cute mon back when Sceptile was here, but nowadays it just gets pressured by so much, that I really dont see myself ever using this on a serious team. One of the main issues I have with Vullaby is that along with it's terrible matchup against every stealth rocker bar Mesprit, it has severe 4MSS, wanting to have Foul Play, U-Turn, Toxic, Roost, Brave Bird, and Taunt. It isn't completely useless though, being a decent check to Lilligant, Musharna, and Vivillon, but I dont really see these few decent matchups it has against a couple mons equivalent to a spot in C-.
