OK... I think I beat myself!
Shuckle...
Level 100 - Atk 22
Power Trick - Atk 465
EVs and IVs - Atk 559
+6 Boosts - Atk 2236 (I think)
Huge power- Atk 4472
OK. Now he is up against:
Noibat...
Level 1 - Def 5
EVs and IVs - Def 4
-6 Def - Def 1
The Attack is ICE BALL...
With Defence curl
With Metronome,
and Shuckle is ice type (Protean)!
Psypoke Says:
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 Huge 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
Max Damage: 116,818,352
But if it's a triple battle, there are two helping hands and flower gifts, so
Max Damage: 262 841 292
Adding on Shuckle's STAB
Max Damage: 394, 261, 938
And if Noibat is Forest Cursed:
Max damage: 788, 523, 876
Correct me if my math was wrong :P