Snorlax is arguable in the top 5 most improved pokémon in Alola, together with Torkoal, Gigalith, Pelipper, and that one other pokémon I'm forgetting about right now. And it didn't get any significant changes to its movepool, it didn't get a stat boost, and it didn't get any change in its abilities either. Figy Berry changed, and that alone is a huge change for Snorlax as together with the previously situational Gluttony ability and its even more situational Recycle access it suddenly has access to what we can actually call reliable recovery. Sets from long ago like Curse setup that simply couldn't handle the power creep are suddenly completely viable again. It also greatly helps it when setting up Belly Drum, because as long as Snorlax's HP stat is even, it can immediately consume its berry after drumming and recover again as if nothing happened at all. Amnesia Snorlax, while rarely seen, is essentially the epitome of special walling, being able to wall even the likes of Water Spout Kyogre and Nasty Plot Porygon-Z.
Snorlax @ Custap Berry
Ability: Gluttony
EVs: 244 HP, 12 Attack, 252 Defence
Impish / Adamant nature
- Belly Drum
- Self-Destruct
- Return
- High Horsepower
Drumboom Snorlax for Battle Royals and doubles. First set up Belly Drum, then at the start of the next turn, the Custap Berry activates allowing Snorlax to gain infinite speed for a turn, with which it can blow itself up with Self-Destruct. Even though Self-Destruct's damage is halved in a Battle Royal, Drum-boosted STAB Self-Destruct has so much raw power behind it that it will still OHKO most pokémon that do not resist it, and it grants you three points for eliminating opponents at once while denying any to your opponents because Snorlax takes itself out, giving you a very solid push to first place in the Royal score at the end, as long as you don't lose all three of your pokémon. It's particularly potent in the mid-late game of the Royal, if at least one opponent only has one pokémon left it can end the battle right there and give you a lot of points to sneak past to first place.
In doubles it works quite similarly, although there it can only eliminate two opponents at once. Run it with a solid support pokémon that can help it out and is immune to Snorlax's attack. Sableye is quite useful as it can use Fake Out to help Snorlax set up, and then use Prankster Foresight in the following turn to surprise any Ghost types the opponent may have, because Prankster has actual priority and therefore goes ahead of the Custap Berry. Sableye can then help later on with something like Prankster Quash to support different partners. Sableye can also run different moves. Psych Up is interesting to copy Snorlax's Drum boost right before it goes boom, while Feint can be used to remove any Wide Guard or Protect attempts the opponent may try to go for to block Snorlax's attack. Telepathy Musharna can set up Trick Room for Snorlax on the opening turn, removing the necessity to run Custap Berry, and can also use Helping Hand to give Snorlax that final boost so it can also OHKO the likes of Metagross with its Self-Destruct. Remember that Self-Destruct hits quite a bit harder in doubles than in Royals.
Snorlax @ Figy Berry
Ability: Gluttony / Immunity
EVs: 244 HP, 12 Attack, 252 Defence
Impish / Adamant nature
- Amnesia
- Body Slam
- Earthquake
- Recycle
Amnesia Snorlax. I ran this in the Simple Symphony competition earlier this year and it's a phenomenal special wall. After a single Amnesia Snorlax is already effectively impervious to special attacks, and with two active Snorlax won't even feel the most powerful special attacks around anymore. Recycle with the berry helps as recovery which a wall needs, and the rest is offensive coverage so that it can actually fight back. The Gluttony ability gives Snorlax the most reliable recovery as it allows it to use the berry earlier, while Immunity can be a viable alternative as it makes Snorlax immune to Toxic. Run this together with physical walls or Acid Armor Baton Passers like Vaporeon. Vaporeon is a fun partner as it can set up Acid Armor and Aqua Ring and then pass to Snorlax, making it bulky on both sides, although Vaporeon has more trouble setting up with Kartana, Tapu Bulu, and Tapu Koko being around nowadays (none of which were present in Simple Symphony, although Serperior was).
Belly Drum Snorlax
Snorlax
Item: Iapapa Berry
Ability: Gluttony
Nature: Relaxed Nature (+Def, - Spe)
EVs: 252 HP/252 Def
Belly Drum
Body Slam/Return
Earthquake
Recycle/Heavy Slam
Preferably to use for trick room, Snorlax's access to Gluttony makes it a perfect candidate to spam Recycle under such conditions with or without Belly Drum. However for the most part, like Snorlaxium Z, this is just a fun set to use even though Snorlax is actually one of the better Belly Drum users out there under Trick Room.
I've run this one as well, terrifying next to Oranguru which can offer it Instruct support and is immune to Earthquake with Telepathy. It's a monster, arguably its best set for Trick Room teams. Just make sure to run 244 HP EVs, not 252, for level 50. For level 50 you want the remainder of your HP EVs when divided by 16 to be 4, this ensures an even HP stat (assuming 31 HP IV). An even HP stat is essential for Belly Drum sets as it allows Snorlax to consume its berry immediately after Belly Drum without any prior damage (Belly Drum damage rounds down, so on an odd stat you'll be half a hitpoint above half and won't trigger the berry), it drastically increases its surviveability when setting up.