Stole this calc from the internet, TLDR: shuckle too good.
User's Team:
Shuckle @ Metronome Level: 100
Ability: Any
IVs: 31 Def
EVs: 252 Def
+Def Nature
Maximum Defense: 614
Defense Curl (Emerald Move Tutor)
Power Trick (D/P/Pt/HG/SS Level 48)
Mimic (FR/LG/E/XD Move Tutor)
Any
Smeargle
Skill Swap
Forest's Curse
Screech
Any
Cherrim
Ability: Flower Gift
Cherrim
Ability: Flower Gift
Opponent's Team:
Noibat @ Any
Level: 1
Ability: Any
Ivs: 0 Def
Evs: 0 Def
-Def Nature
Minimum Defense: 4
Walrein
-Ice Ball
-Any
-Any
-Any
Greninja
Ability: Protean
Medicham
Ability: Pure Power
Have Smeargle use Forest's Curse on Noibat to add a Grass type
Have Smeargle use Skill Swap with Greninja to get Protean
Have Smeargle use Skill Swap again to give Shuckle Protean
Have Walrein use Ice Ball
Have Shuckle use Mimic to copy Ice Ball
Have Shuckle use Defense Curl for 2x power Ice Ball
Have Shuckle use Defense Curl until Shuckle is at +6 Defense
Have Shuckle use Power Trick
Have Smeargle use Skill Swap on Medicham to get Pure Power
Have Smeargle use Skill Swap again to give Shuckle Pure Power
Have Shuckle use Ice Ball until Metronome is at maximum potency
Have Cherrim use Sunny Day to activate Flower Gift for both Cherrim
Have both Cherrim use Helping Hand on Shuckle
On Ice Ball's 5th hit, get a critical hit
To make things simple with the calculation, I'm keeping out the super effective and critical hit calculations until at the end.
Psypoke's Damage Calculator:
Your Pokemon:
Shuckle @ Metronome
Level: 100
Type: Bug/Rock
Att/Spec Att: 614
Def/Spec Def: -
Stat Modifiers: 6
Ability: Pure Power
Your Opponent:
Noibat
Level: 1
Type: Normal (for easy calculating)
Att/Spec Att: -
Def/Spec Def: 4
Stat Modifiers: -6
Ability: Ignore Ability
Your attack: Ice Ball
Item: Metronome
Number of Consecutive Uses: 10
Global Battle Effects:
Sunny Day
Defense Curl
Helping Hand
Partner's Flower Gift
Results:
Defense Curl boosts the base power for Ice Ball with a 2.0× multiplier
Helping Hand strengthened the power of Ice Ball with a 1.5× multiplier
Shuckle's Pure Power boosted its Attack with a 2.0× multiplier
Shuckle's partner's Flower Gift boosted its Attack with a 1.5× multiplier
Shuckle's Metronome strengthened the power of Ice Ball with a 2.0× multiplier
Shuckle gets the Same Type Attack Bonus (STAB) for Ice Ball
MAXIMUM DAMAGE: 26,737,002
26,737,002 x 1.5 (additional Flower Gift) = 40,105,503
40,105,503 x 1.5 (additional Helping Hand) = 60,158,254
60,158,254 x 1.5 (new Critical Hit multiplier) = 90,237,381
90,237,381 x 8 (3x Weakness) = 721,899,048