Iwaparesu
Type: Bug/Rock
Base Stats
HP: 70
Attack: 95
Defence: 125
SpAtk: 65
SpDef:75
Speed:45
70HP is a bit of a let down... but it has decent Attack and great Defence. Its SpDef is pretty crap and its speed is pathetic. This is an issue for Iwaparesu, but it gets a move to fix its speed and give it 190 Atk.
Typing
0.5x Normal, Poison
x2 Water, Steel, Rock
It's not great typing, Resisting 2 of the least used offensive types and weak to 3 fairly common offensive types. At least it has no 4x weakness, but it is exposed to 25% from SR and is affected by all other hazards.
Abilities
Study: Can't be 1hkoed.
Shell Armor: Can't be hit by a Crit
Breakable Armor: When hit by a Physcial attack -1Def, +1Spd
Nothing special, Breakable Armor and Study
As i was looking threw the new moves, one move stood out, and that move is shell break. I went straight to Blastoise with excitment and no... Blastoise doesn't get shell break. So I'd say Iwaparesu looks to be the best physical user of shell break. According to Serebii, Shell Break Adds +2 Atk, SpAtk and Spd, but lowers Def and SpDef. If this is correct, IMO this is the best stat building move in the game, few Pokemon get it though.
Before I get to the possible movesets, here is everything Iwaparesu learns.
Bold= Good Moves (only will highlight once if the move shows more than once)
Level Up
Lv.1 Shell break
Lv.1 Rock Blast
Lv.1 Withdraw
Lv.1 Sand-attack
Lv.5 Rock Blast
Lv.7 Withdraw
Lv.11 Sand-attack
Lv.13 Faint Attack
Lv.17 Knock Down
Lv.19 Rock Polish
Lv.23 Bug Bite
Lv.24 Stealth Rock
Lv.29 Rock Slide
Lv.31 Slash
Lv.38 X-scissor
Lv.43 Shell Break
Lv.50 Flail
Lv.55. Rock Wrecker
Lv.1 Rock Blast
Lv.1 Withdraw
Lv.1 Sand-attack
Lv.5 Rock Blast
Lv.7 Withdraw
Lv.11 Sand-attack
Lv.13 Faint Attack
Lv.17 Knock Down
Lv.19 Rock Polish
Lv.23 Bug Bite
Lv.24 Stealth Rock
Lv.29 Rock Slide
Lv.31 Slash
Lv.38 X-scissor
Lv.43 Shell Break
Lv.50 Flail
Lv.55. Rock Wrecker
TM List
TM01 Claw Sharpen
TM06 Toxic
TM10 Hidden Power
TM15 Hyper Beam
TM17 Protect
TM21 Frustration
TM22 Solarbeam
TM23 Knock Down
TM26 Earthquake
TM27 Return
TM28 Dig
TM32 Double Team
TM37 Sandstorm
TM39 Rock Tomb
TM40 Aerial Ace
TM42 Facade
TM44 Rest
TM45 Attract
TM48 Sing A Round
TM65 Shadow Claw
TM68 Giga Impact
TM69 Rock Polish
TM71 Stone Edge
TM75 Swords Dance
TM76 Bug Opposition
TM78 Level Ground
TM80 Rock Slide
TM81 X-scissor
TM84 Poison Jab
TM90 Substitute
TM94 Rock Smash
TM06 Toxic
TM10 Hidden Power
TM15 Hyper Beam
TM17 Protect
TM21 Frustration
TM22 Solarbeam
TM23 Knock Down
TM26 Earthquake
TM27 Return
TM28 Dig
TM32 Double Team
TM37 Sandstorm
TM39 Rock Tomb
TM40 Aerial Ace
TM42 Facade
TM44 Rest
TM45 Attract
TM48 Sing A Round
TM65 Shadow Claw
TM68 Giga Impact
TM69 Rock Polish
TM71 Stone Edge
TM75 Swords Dance
TM76 Bug Opposition
TM78 Level Ground
TM80 Rock Slide
TM81 X-scissor
TM84 Poison Jab
TM90 Substitute
TM94 Rock Smash
Egg Moves
Endure
Iron Defence
Night Slash
Sand Tomb
Counter
Curse
Spikes
Block
Iron Defence
Night Slash
Sand Tomb
Counter
Curse
Spikes
Block
Possible Movesets
Basic Shell Breaker
Iwaparesu @ Life Orb/Leftovers/Lum Berry
Ability: Sturdy/Broken Armor
Adamant/Jolly Nature
EVs: 4HP/252Atk/216/Spd/36SpDef
~Shell Break
~X-scissor
~Rock Slide/Stone Edge
~Earthquake/Night Slash/Substitute
The item is up to you, but Life Orb may be needed to turn 2hkos into 1hkos. Leftovers is good if your running Sub and Lum berry allows Iwaparesu to Set up without worrying about status. Both abilities are average, if you don't mind losing Defence for Speed then go Broken Armor. If you don't like that, run Study (unlikely for Iwaparesu to be 1hkoed). Shell Armor can be used to block crits... but they shouldn't even happen anyway. Run Max speed for Adamant, the EVs given above are for Jolly, it allows you to out-speed positive Base 130+ after a Shell Break.
The moves are very basic. Shell Break for the +2 Atk +2 SpAtk +2 Spd. Dual STAB is always nice, and you will probably be moving first so the 30% flinch on rock slide may get annoying for your opponent. 4th Move filler should probably be Earthquake/Sub. Night slash is okay if your having accuracy troubles, but his dual STAB doesn't really require a dark move filler. Earthquake for coverage, Sub for being safe for a turn. Curse, Swords Dance and Rock Polish are all great moves, but simply outclassed in this case.
It is walled by non grounded Steels, but usually non grounded steels have a secondary type which Iwaparesu can hit for neutral damage.
I'm probably comparing this to the 4th gen metagame, but I think it will to well in 5th Gen.
Support Hazarder
Iwaparesu @ Leftovers/Lum Berry/Chesto Berry
Ability: Shell Armor
Carful Nature (-SpAtk +SpDef)
EVs: 252HP/4Def/252SpDef (Fixed from 128hp/128def)
~Steath Rock
~Spikes
~Stone Edge/Rest/Block
~X-Scissor/Rest/Toxic
This set would be better in 4th gen, now that defog screwes up everything on the field (NVM). Still, it does its job. Block is interesting, it can be used on some stupid toxic staller or something that is also setting up, then Iwaparesu can set up.. Something like Spiritomb is an easy set-up target. I think 1 attacking move is necessary, or just toxic. Rest is for recovery, supported by Chesto/Lum. Sand Storm works well with this.
Conclusion
Iwaparesu may be a threat, I assumed it was going to OU or BL... but everyone is saying UU =(. It can reach up to 634atk and over 390 speed with one boost, not to mention the SpAtk. It makes me wonder if Shell Break's effect is a typo. I personally think it can do well in any tier, (even Ubers).
Credit to Serebii.net for providing ability and moveset info. Bulbapedia for Sprites.