From the Super Pony Squad/SPS Pokémon episode titled “Battle of the Gods”:  
Chaos 0 from another timeline and another returning foe have entered the Super Pony Squad’s timeline.
 
With Chaos consuming the power of the Z-Crystals on Nessoasis, the squad are too late as Chaos soon becomes Perfect Chaos as he consumes one last Z-Crystal.
 
But before Perfect Chaos can conduct his rage of destruction, the other lining foe reveals himself as none other than Tarak Tara Karn: The God of Destruction that had been transported through time from another dimension.
 
With Nessoasis at stake with the 2 Gods of Destruction brawling, the squad have no other choice but to go and stop then before something bad will happen. With the arrival of the Tapu Guardians willing to help, this’ll be their only chance to take down Perfect Chaos and defeat Tarak Tara Karn for good!