What is the best Pokemon in sun and moon?

I think best pokemon in sun and moon is Toxapex, Toxapex has a very high special defense and defense. If you use this moves ,Toxapex can be crazy strong.

[Lvl. 33]Recover-To recover[obviously]

[Lvl. 58]Liquidation-Good water type move to attack.

[Evolve. 1]Baneful Bunker-Uses to protect from moves and can poison the target if the move is physical.

[Lvl. 21]Toxic- Used to chipped away HP.

The only way to get Toxapex is to evolve it from Mareanie. To get Mareanie, you need to go to route 9 and find a Corsola and do an SOS battle. Corsola has a 5% chance to appear while fishing. You might want to stock up on Adrenaline Orbs. Also, bring a pokemon that knows false swipe or hold back. The Corsola might call in for another Corsola so keep using the Adrenaline Orbs. Hoped this helped! [You need a lot of patience for this]