Gen 6 Need help with my Cloyster team

[Jako27]

So this is the current team (Gen 6 OU)

Big fat snek (Serperior) (F) @ Leftovers
Ability: Contrary
Shiny: Yes
EVs: 56 HP / 200 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Leaf Storm
- Dragon Pulse
- Substitute
- Leech Seed

Fat (Diancie-Mega) @ Diancite
Ability: Clear Body
EVs: 4 Atk / 252 SpA / 252 Spe
Naive Nature
- Moonblast
- Diamond Storm
- Hidden Power [Fire]
- Substitute

Fat 2 (Kyurem-Black) @ Life Orb
Ability: Teravolt
EVs: 4 Atk / 252 SpA / 252 Spe
Mild Nature
- Ice Beam
- Earth Power
- Fusion Bolt
- Roost

phatty (Excadrill) @ Leftovers
Ability: Mold Breaker
EVs: 252 HP / 4 Atk / 252 SpD
Careful Nature
- Earthquake
- Iron Head
- Rapid Spin
- Stealth Rock

Ur dead lol (Cloyster) @ Focus Sash
Ability: Skill Link
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Shell Smash
- Icicle Spear
- Rock Blast
- Ice Shard

monkiboi (Infernape) (M) @ Life Orb
Ability: Blaze
EVs: 100 Atk / 156 SpA / 252 Spe
Naive Nature
- Close Combat
- Fire Blast
- Gunk Shot
- Grass Knot

The team has been working ok so far, but I still think it could use some improvements. I started playing Showdown 4 days ago, so I'm really not that experienced with team building and such.

The only real criteria for the team is that I want to keep Cloyster, and preferably Serperior. Please help!

 

[TPP]

Welcome to Smogon! I'm locking your RMT for the time being as the forum rules require that you provide at least 3 lines of descriptions for each Pokemon to explain their roles. Please read the rules carefully and take a look at Team Showcase to see the level of detail we require. PM me with updated descriptions and I'll be happy to unlock this.