Just want to make sure we are all on the same page. 97.6% of teams have a priority move on them (mostly bullet punch) So this isn't actually competitively viable. So as long as everyone knows that this set is just for fun and not serious I think we can all be friends here ^_^
Teams maybe, but not pokemon - team preview is there for reason. Even if you can't escape the perils of priority, that doesn't mean it completely shuts down Riolu. If you suspect a priority move... just use plain Roar, the priority user gets phazed out and you can begin the chain again. Of course that means Riolu has to take a hit, but that doesn't mean he can't.
284hp is measly, of course, but his Defense can alleviate that somewhat. Plus Riolu gets Iron Defense with priority.
With Eviolite, it's 294
With Iron Defense, it's 392
With both, it's
588
You're no Shuckle but you still take a few hits. Priority is mostly physical, and 174 Special Defense means you should be able to handle at least vacuum wave. The real problem is going to be priority taunt and priority status, not attacking moves.
Name: Assist-lite
Riolu (M) @ Eviolite Trait: Prankster
EVs: 200 HP / 200 Def / 108 Spd (271 hp, 273 Def Eviolite, 546 w/ Iron Defense
Bold Nature (+Def, -Atk)
- Copycat
- Roar
- Agility
- Iron Defense
Ultra-gimmicky, but it illustrates the point. If anything is stupid enough to give you the three turns to set this one up, only Extremespeed, Sucker Punch, Fake Out, Quick Attack and Ice Shard can catch up with you. It outspeeds max speed Whimsicott, the fastest Prankster. At this point, the only thing getting in your way is unlucky crits, Magic Coat, Suction Cups, Soundproof, and Magic Bounce, and as far as I know, Roar doesn't activate Red Card. And if you see Xatu and Espeon on your opponent's team, you should be making a point of luring them out. You can continue this for at least 32 turns, too.
Better yet, and more viably, have something like Scizor or Gorebyss BP Iron Defense + Agility to this Riolu, and you keep its two extra moveslots open for Circle Throw, Death Gambit, Substitute, or moves that Prankster can make nice use of. You may even be able to forego Eviolite for Leftovers. In this case, Rain might be a great thing to have on your team too, as a way of removing sand and providing support for Gory and Scizor.
To me, this actually takes only a small bit of effort for a massive payoff, assuming you're fitting it into an overall scheme of a hazards team, so "just a bit of fun" seems a bit shortsighted. Give it three turns, two of which it doesn't even need to be on the field for, and it could purge a team, leaving you to mop up Reuniclus or Gliscor.