I absolutely love trolling on showdown, and perhaps the most aggravating Pokemon out there is roar + copycat riolu. Unfortunately the biggest thing that ruins it, and many other trolling Pokemon, is priority. So what tier can this Pokemon run free most in?
OU:
Well, most tiers have a decent amount of priority. OU has most noticeably Conkeldurr and Scizor. But lucario, Mienshoa, clyoster, Mamoswine, occasional weavile and much more make an appearance so it's best not to stride around there.
UU:
While not as bad as OU, Priority can still be an issue around here. Hitmontop and Mienshoa specifically love it here. Fake out particularly doesn't like Riolou. Mien will easily get past, and Hitmontop's Mach punch doesn't go well either. Not to mention once again the fearsome weavile and the very occasional mew sets that could include. Another thing to watch out for in UU is a few RU threats like Gallade which I'll be apporcahing in a mo
.RU:
Well, this a little more free to roam. However, a few popular Pokemon still like to ruin Riolou's fun around here. gallade and it's Shadow sneak love to punish it. and a few of the fake out users like Medicham again hate Rioulou and prevent it from Trolling about. Also look out for spiritomb, and snover which will ruin everything with hail.
NU:
Ah,,Riouls home..you'd expect it to workhere well. But unfortunately, it still has problems. Khangaskhan is one of the best Fake out users going, and it's also very common around here. although soem are rarer, we have a couple of quicj attacker or Extreme speed users lurking in the shadows, such as zangoose. Aqua Jet from Sammurott, another local hero, is equally dangerous.
It looks like Riolou is having a hard tie. But there is one place for it.
Ubers:
You'd never expect it to come here, but there are several reasons it should. for one, it's not hard to set out your hazards here. And as long as you keep your spinner alive to eliminate hazards on your side, then it'll be a barrel of laughs. Also, other than EXK Acreus for which you should be carring around a counter for anyway, and Girtina, there isn't really any serious priority users. This means that it is very easy to keep up the trolling for much longer periods, and with the right team mates, possibly win the game completely.
Hope I helped!!