Words cannot describe how disappointed I am in everyone saying 'Yache Berry blocks all five hits of Ice Shard on Shoddy so Cloyster isn't a counter.' That is the stupidest thing I have ever heard. It's a well known glitch which has been pointed out in this thread. It will be fixed.Glitch or not. As long as it is still that way, we will take it into account.
With that out of the way, 252/252 HP/Def Relaxed/Impish Cloyster takes 71% max from SD Outrage. It switches in on the Swords Dance, Icicle Spears/Ice Beams, then Ice Shards for the KO. If Stealth Rocks aren't up, you win barring a CH (I'd use Ice Beam so you have the option of Battle Armor) or a freak Garchomp with Fire Blast over Fire Fang. If Stealth Rocks are up but Sandstorm isn't, it's the same thing. If both are up, you need to slap on Shell Bell (so you're healed before the buffering) and pray Chomp pulls less than 69% to live. All this is extremely specific and you have to be incredibly careful about not letting Cloyster take any damage beforehand.
Defender HP: 304
Move Damage: 241 - 284
Damage: 79.28% - 93.42%
On a Jolly Garchomp, with max Atk, SD up using Outrage on a Cloyster with a +defence nature, & max HP & Def. If Chomp is Adamant for whatever reason, it jump to 87-102%.
That is why Cloyster is not a Garchomp counter. It can be used to deal with Garchomp, since most Stealth Rockers are suicide leads and so they can be spun, but ghost types block that and not everyone wants to carry a spinner or even a Cloyster for that matter. Now please, can we drop it?If you want it to be dropped, it has to stop being bought up in the first place.
Specs Tangrowth is also not a Garchomp counter, where does that idea come from? Scarf Cressy could work but is otherwise outclassed and quite mediocre.