Uh...this is my first ever time trying something like this; sry if my opinion is questionable. Lol. Ok, so...i want to train a Shuckle for the Vgc Pkmn World Championships in the Master Division. I really believe that Shuckle's true potential can take him that far...as well as other Pokemon who deserves a Champion's shine. With that bein' said...my strategy for Shuckle would be this:
Item: Leftovers/Quick Claw
EVs: 4 HP/ 252 Def/ 252 Sp.Def
Now, I don't really know the logic about Pokemon competitive play...so if this Shuckle is bad, then I'm sry. At least, I tried. Anyways, here are the reasons why I think this Shuckle could be good:
First off, I know that the only move, Shuckle has is Infestation. But, the reason why it has that is cuz to not only avoiding "Taunters", but, to also troll a lot of Pokemon, so that, your teammate can either: cripple em' or destroy em', when they're trapped in Infestation.
Stealth Rock and Sticky Web are obvious choices for Shuckle. I couldn't really decide between the two, so I just put both of them in. That way, in case some "Rapid Spinner" gets rid of one status, Shuckle can just bring the other one in, just to possibly sucker the opponent into using Rapid Spin multiple times. If you get both statuses in, then: #1: Thank the RNG gods and Shuckle. #2: Get rid of the "Rapid Spinner"!
Shuckle's last move: Power Split...was a very odd choice that I added, but, when I researched its usefulness, I realized that it could be extremely powerful to use.(i hope.)
Just to give an example of what it do, here are the kinds of Pokemon that Shuckle could severely cripple with Power Split(*Also, on a sidenote, if you're the kind of ballsy person to go to the Extreme, then, make sure you use Trick Room for some, if not all, of these "big bois"!):
Metagross(Without Bullet Punch)
Scizor(Without Bullet Punch)
This, can also work against Pokemon with Sp.Atk, although, this is slightly more dangerous:
(This is not 100% guaranteed. I just want to give Shuckle every opportunity possible.)
Now, when it comes to Shuckle's items and stats:
Maximum defences possible. No Speed. No Attack. No Sp.Atk.(Unless if you want to raise the chip damage for Infestation, a little bit.) Nothing. For items: Leftovers may help Shuckle use its Sturdy ability again, if you're lucky. Quick Claw is just in case, someone ruins Trick Room for Shuckle or you can pray to the RNG gods again, in case, you troll your opponent again before they troll you.
The only things that could ruin this Shuckle are:
Things that can get rid of Trick Room
and Z-Moves that One-Hit K.O's Shuckle.
I hope this strategy for Shuckle is good for you guys or girls. Make sure to tell me what you think about it! (If I break any rules about typing my opinion, then sry. Like I said: first time I tried this.)
(I don't even know how to post an answer correctly...jeez.)(-_-)