Most Wall/Stall pokemon usually dont have good atk or sp.atk stats, but I have made a wall that can sweep and tank damage from even sweepers.
Pokemon: Toxapex (Poison, Water) (Top 5 Highest def and sp.def stats btw)
Moves: Recover, Toxic/Toxic Spikes, Venoshock, Stockpile
Ability: Merciless
Nature: Calm
Item: Black Sludge
Description
Merciless: Moves become critical hits if the target is poisoned
Calm Nature (More Sp.def, less Atk)
Black Sludge: Heals Poison Type Pokemon every turn (same amount as leftovers) and Damages Pokemon that arent poison.
Notes
Toxapex has more sp.atk than atk and raises sp.def if needed, thats why go with calm nature.
Toxapex is a Poison type, so it wont be damaged by Black Sludge and will be healed instead.
Better to use Toxic as you are a wall and wasting a turn wont really affect your hp, as using two Toxic Spikes you wont have to waste a turn and get the same poison affect (Badly Poisoned) as Toxic, but if any pokemon like flying type or levitate ability are in play, Toxic Spikes wont work, so just use Toxic as its very important for you to have the pokemon poisoned for the setup and its garenteed to poison. Your Choice.
Setup
So the battle starts and the foe sends out pokemon, while I would send out my Toxapex.
Use Stockpile three times to make your Toxapex really buff and tank any attack and use recover to recover your HP while in the process of stockpiling (Max 3)
Stockpile raises users def and sp.def stat by one stage and can be used 3 times.
Now once you got off 3 stockpiles, you can now use Toxic (Recommend this instead of toxic spikes)
Now heres where the fun begins 😈😈😈
Sweep Time
Lets explain first, Venoshock has a attack of 80, in its description it does double damage if the target is poisoned, so raise that to 160 plus STAB (Same type attack bonus) which raises the attack by 20% I believe
So 20% x 80 (just to be safe) which I would believe is extra 16? Very sad, doesnt matter.
Now heres the best part, the Merciless ability... which if the target is poisened, it will garenteed a critical hit, for those who dont know, crits add double damage, basically 100% extra.
So 80 = 160 (Venoshock Extra Description)
+ 16 (Stab)
X 2 (Critical Hit)
= 336 base damage
And the strongest move ever has a Base Stat of 150 or 160 I think.
Anyway thats it basically...
Well, I'd love to see yalls reaction, and I did try to make things simple...
May have had some mis-cacultaions, but its way more than enough, plus toxic could solo anyway.
Well... God of Competitive out.
Edit: Caculation was wrong, base power is more than 336 tho, enjoy sweeping: