Pokémon X and Y Walkthrough, Pokémon Move Sets: Snorlax
(Please note that the recommendations below are largely made for in-game play. A Snorlax in a competitive environment will likely make use of different moves to accommodate for smarter, more adaptive opponents. If you have a different Snorlax you'd like to shout out to the Pokémon world, toss it in the comments.)
The ultimate in sleepy pokémon (though perhaps not the laziest, not since the third generation), Snorlax has long enjoyed a spot as one of the best normal-type pokémon ever created. Since the first generation it has proven that normal-types, though occasionally drab, are not to be underestimated. You really can't go wrong with a Snorlax on your team.
Snorlax begins life as little Munchlax. Level Munchlax up once it has achieved a high level of friendship (in Pokémon X and Y this is best done via Pokemon-Amie) and it will evolve into a Snorlax.
None. Immune to Ghost.
Ahh, the extremes. Snorlax is blessed with a truly monstrous HP stat, one of the highest in the game, which will allow it to weather virtually any attack at least once. Attack and Special Defense tie for second place, both of them quite monstrous. This pokémon is made to ward off hits and deliver them in exchange. Defense is a little low for comfort, though its HP makes up for some of this loss; Special Attack is low and largely negligible to Snorlax builds. Snorlax's primary weakness is its pitiful Speed, which, depending on your build, isn't always a bad thing anyway.
Immunity: This pokémon is immune to the effects of poison. This wouldn't be such a big deal... except that it blocks Toxic, a popular moveset choice and a good way for taking down walls and tanks like Snorlax. An overall excellent ability in multiplayer battles where Toxic is common.
Thick Fat: The pokémon takes half damage from ice- and fire-type attacks. It's a shame that Thick Fat has some stiff competition, as it really is a good ability, especially in a world where Charizards are such common competitors. Nevertheless, I think Immunity takes the win in the ability race unless you plan on using Rest a lot.
Gluttony: The pokémon will eat a held berry at half of its health, rather than the normal one-quarter. Not a terrible ability, but Snorlax is a popular target for Leftovers. If such is the cae, Gluttony will be useless most of the time. This is a hidden ability.
Snorlax's stats and wide movepool allow it to move in a variety of different directions, though most will focus on utilizing Snorlax's ridiculous bulk. The first option is to use what is basically Snorlax's signature move, Rest, for offensive purposes. Pair Rest with Sleep Talk and use it whenever Snorlax is getting tired. That way you can continue to do awesome amounts of damage while Snorlax is slumbering via your other two moves. Return is a good STAB option, as is the damaging-but-devastating Double-Edge; anything else physical that you might want can fill the final slot. I prefer Earthquake, though this brings with it the possibility of completely missing flying-types. Fill whatever hole your party requires.
Looking for a slight (and by slight I mean massive) Attack boost? Toss out Sleep Talk in exchange for Belly Drum. So long as your opponent doesn't hit you with a fighting-type move on the first round your Snorlax will probably survive long enough to Rest. Once it wakes up you'll be ready to rumble with moves that can annihilate anything.
You also have the option of tossing Rest out the window completely and turning Snorlax into a pure attacking machine. In this case, keep your two moves from before and add in a few supplementary measures to cover more ground. You have plenty of options, ranging from Brick Break to Crunch to Heavy Slam to Wild Charge. So long as you don't overlap on types and try to spread out your super effective targets your Snorlax will be quite a powerhouse.
Last, Snorlax has the capacity to be a decent Toxic user. After poisoning your foe, use Protect to ward off attacks, Amnesia to skyrocket Snorlax's Special Defense (assuming you aren't in a scrap with a fighting-type, of course), and Rest when necessary. This wastes Snorlax's Attack stat, though, so I'm not sure if it's the best use of such an effective wall.
EV / Super Training
The majority of Snorlax users should focus on developing HP and Attack. HP will offset Snorlax's awful base Defense, while Attack will turn it into a one-hit powerhouse. If you decide to head down the Toxic route instead, swap Attack for a full dose of Defense.
Catching a Snorlax
The most obvious way for snagging a Snorlax is to simply proceed through the story. Once you reach Route 7 you'll run afoul of one sleeping on a bridge, and you'll have the chance to fight and capture it. If you don't manage to catch it on the first try, return after beating the Elite Four and the champion for another round.