THE GIANT oyster...

Its Purple. The face makes me lol as it reminds me of a certain inside joke.

Pros
+ Absorbs Earthquake
+ Spikes AND Spins
+ It Explodes to kill the unsuspecting Blissey
+ Walls Tyranitar somewhat.
+ No Critical Hax with Shell Armor

Cons
- No HP or Sp.Def
- Rock and Fighting still hurt

Counters: Special Attacking Pokemon. CB Fighting/Rock Pokemon.

Cloyster can absorb Earthquakes so it makes for an AWESOME switch. Sadly, Rock Slide hits for super-effective damage and Focus Punch/Brick Break/HJK hit for neutral damage and can dent this sucker pretty well. Spikes + Rapid Spin is always a plus. Rest is a bad idea on the pokemon merely because its HP stat is too low. Beware special attacks. Fire attacks can still pack a brutal punch on this pokemon.

Cloyster (M) @ Leftovers
Trait: Shell Armor
EVs: 252 HP / 56 Atk / 164 Def / 36 SAtk
Relaxed Nature (+Def, -Spd)
- Ice Beam / Explosion
- Rapid Spin
- Spikes
- Explosion / Surf

The really only useful set. With that monster defense, this thing can be thrown into a CB Mence EQ/HP:Fly and then own it up with Ice Beam or just start Spiking. Bliss will undoubtably try to wall, but you spike then boom. Rapid Spin can help to remove current spikes. Btw, no crit hax = hawt.

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UU/BL Play is where this pokemon truely shines. Spikes is awesome in UU because of the quick, offense style of battle. This pokemon can also dish some damage too.

I'd suggest pairing this pokemon with Meganium simply because Meganium can take the force of many special attacks while you have Cloyster to take the Aerial Ace/HP:Fly attacks.

I would also like to add that Cloyster is the only poke that can pull off a Spike Cannon (Corsola and Omastar are crap at using it).So if you need to break a Sub,don't have a Rock Blaster and need to cause damage *cough*Ninjask*cough*,Cloyster with Spike Cannon is the way to go.

Or you could try Icicle Spear for STAB. I'd also include, for a pro, that it's one of the only good spikers that can escape Magneton's Magnet Pull.