Highest damage dealt in Pokemon?

My partner said that he had read about the fact that the highest possible attack in a pokemon battle in one turn is more than 480,000,000 (I forget the exact number).

And the only one that can do this is Shuckle.

I know that Shuckle has unique statistic distribution as stated in the trivia on Bulbapedia;

Shuckle has the most extreme stat distribution of any Pokémon, being either the best or in the bottom three of every base stat category:

• Shuckle has the highest base Special Defense stat and ties with Mega Aggron and Mega Steelix for the highest base Defense stat, all being at 230.
• Shuckle has the lowest base Attack and Special Attack stat of all Bug-type Pokémon.
• By using Power Trick, Shuckle can temporarily reach a base Attack stat of 230, which would be the highest of all Pokémon.
• Shuckle is tied with Munchlax for the lowest Speed base stat of all Pokémon.
• Shuckle is tied with Feebas and Bonsly for the lowest Special Attack base stat of all Pokémon.

But is it true that Shuckle can deal more that 400,000,000 damage in one turn? If it is true, what strategy do I use to do that?

This Youtube video shows the 2 strongest possible attacks. With Shuckle wearing the crown with a whopping 722 Million damage in a single hit.

It does take a lot of planning and stat changes. Everything has to be right. The ally Pokémon, the correct move set, the correct move set of the enemy and the enemy's Pokémon.

Before you start: Grass < Ice. Add Forest Curse for an 8x Weakness Setup:

1. A level 100 Swampert holding a Metronome
   31 Atk IV's
   252 ATK EV's
   Attack boosting Nature
   Moves: Defense Curl & Ice Ball
   From Pokemon Emerald(Only way to get Swampert to learn defense curl from the Move Tutor)

2. Triple Battle:

   • Enemies - Noibat(0 EV's/IV's in Defense, -Defense Nature)
   • Kecleon & Medicham
   • Ally Shuckle uses Power Trick and Power Split on your Swampert.
   • Use Defense Curl and let ally use Swagger on Swampert to increase Attack
   • Give enemy Noibat Forest Curse. Creating a flying, dragon, grass pokemon with an 8x Weakness to Ice.

3. Skill swap the Ability Protean from an enemy to Swampert. Use Ice Ball so Swampert gets an Ice typing. Creating Ice Ball STAB increase(x1.5)
   Skill swap Pure Power from enemy to Swampert(From Medicham)

4. Use Screech on Noibat for -6 Defense

5. Use Ice Ball to get Metronome to maximum effect (Don't attack Noibat)

6. Let 2 Cherim use Sunny Day, Transform (activating Flower Gift) and both use Helping Hand on Swampert

Now, if Swampert deals a critical hit on his 5th hit on Noibat he will do 566.702.568 Damage.

Now Shuckle can do even more by repeating the process but with a Shuckle (mimicking Ice Ball) and deal 721.899.048 damage!