In this post, /u/Poshul pointed out that Shuckle would become a beast with even a small boost to HP. Well, I figured I'd give Transform Mew and Shuckle a shot to see if it could work. Here's what happened.

The Team:

Shew (Mew) @ Grip Claw / Leftovers

Ability: Synchronize

EVs: 252 HP / 4 SpD / 252 Spe

Jolly Nature

- Transform

- Protect

- Fake Out

- Magic Coat

Muckle (Shuckle) (M) @ Chesto Berry

Ability: Contrary

EVs: 4 HP / 252 Def / 252 SpD

Bold Nature

- Infestation

- Toxic

- Shell Smash / Knock Off / Power Split

- Rest

Lanturn It Up (Lanturn) (M) @ Sitrus Berry

Ability: Water Absorb

EVs: 252 HP / 40 Def / 216 SpD

Calm Nature

- Soak

- Heal Bell

- Scald

- Protect

Me So Thorny (Ferrothorn) @ Rocky Helmet / Leftovers

Ability: Iron Barbs

EVs: 248 HP / 8 Atk / 252 Def

Impish Nature

- Leech Seed

- Knock Off

- Power Whip

- Protect

Pain Train (Heatran) (M) @ Air Balloon

Ability: Flash Fire

EVs: 180 HP / 252 SpA / 76 Spe

Modest Nature

- Heat Wave

- Earth Power

- Will-O-Wisp

- Protect

Void Staff (Excadrill) (M) @ Choice Scarf

Ability: Mold Breaker

EVs: 36 HP / 252 Atk / 220 Spe

Adamant Nature

- Toxic - Iron Head - Drill Run - Rock Slide

Explanation:

Max HP, max Speed Mew generally only uses Transform before becoming a huge HP version of Shuckle. Fake Out, Protect, and Magic Coat are all situational. Grip Claw means your Infestations last 7 turns instead of 4 or 5. Leftovers is for more reliable recovery.

Max Def and SpDef Shuckle is there for Mew to Transform into. Keep in mind Transform copies everything EXCEPT HP, which is why Mew runs max HP and Shuckle runs max defenses. Moves are fairly straightforward. Infestation and Toxic for damage each turn. Rest heals HP and status, and uses up turns for Mew who has very little PP after Transform. I prefer Shell Smash (with Contrary) to boost defenses over Knock Off or Power Split, but they can all work.

Now for the team to complement Mew once Shuckle goes down...

Lanturn is a decent Special tank with Soak to enable Mew to use Toxic on Steel and Poison types. Scald comes with a chance to burn. Heal Bell is a bit redundant, but can wake up Shuckle from Rest and get rid of status on itself. Protect to stall turns.

Ferrothorn is the go-to physical tank. Leech Seed, Knock Off, and Protect are all awesome for the stall game.

Heatran is the answer to Poison and Steel types that mess up Mew's Toxic. Will-o'-Wisp burns things. Heat Wave and Earth Power do serious damage to Steel and Poison types, respectively. Protect to stall an extra turn.

Lastly, Scarfed Mold Breaker Excadrill can deal with annoying things like Magic Guard Clefable (Iron Head) or Magic Bounce M-Sableye, Espeon, Xatu, M-Absol, etc. with Toxic.

What I learned:

First, a Shuckle with the HP of Mew is a SERIOUS TANK. It takes a lot to hurt this thing. However, it's weak to Leech Seed, high powered or boosted Water or Rock attacks (before Shell Smashing), and Taunt (which means you can't use anything but Infestation or Knock Off). Heal Bell / Aromatherapy are extremely annoying to deal with. Also, not something you would normally think about, but Pressure can mess up Mew since it only has 5 PP on each move.

That said, every strategy has weaknesses. The potential of Mew/Shuckle - provided your opponent can't shut it down early - is enormous. I can't emphasize enough how damn impossible this thing can be to kill.

Replays:

(Note: Yeah, these are low on the ladder. I dare you to fully test a gimmicky setup like this without losing a ton of elo.)

http://replay.pokemonshowdown.com/doublesou-253351376

leftovers, opponent rage quits

http://replay.pokemonshowdown.com/doublesou-253353740

grip claw, opponent rage quits

http://replay.pokemonshowdown.com/doublesou-253356758

same thing

http://replay.pokemonshowdown.com/doublesou-253357735

Opponent wasn't very good, ended up using the rest of the team to do most of the work.

Sorry I couldn't get some better replays, Mew/Shuckle is a serious rage inducer and makes a lot of people give up pretty quickly. Additionally, none of the players in these replays were particularly good at teambuilding or battling. Oh well, I tried.

Let me know what you think, if this goes over well I can do more analysis like this. If you think this strat sucks and should never be used, feel free to tell me. I just thought it would be cool to take an arbitrary idea like this and test it out.

If you wanna give this a shot yourself, the team is right up there ^ ^ ^ Feel free to change it up and post any battles you win with it.

Thanks for reading!