Pokémon X and Y Walkthrough, Pokémon Move Sets: Alakazam
(Please note that the recommendations below are largely made for in-game play. An Alakazam in a competitive environment will likely make use of different moves to accommodate for smarter, more adaptive opponents. If you have an Alakazam of different stripes and want to share, toss it in the comments for all to behold.)
Long one of the poster boys of the psychic-type fraternity, Alakazam is an all-or-nothing pokémon. It's as strong as a zen master and as frail as a twig, and if it fails to land a kill on the first turn it will probably go down instead. Fortunately, Alakazam more than has the capacity to wipe out its opponents - especially now that it can undergo a Mega Evolution...
Alakazam is one of those pokémon that everyone wanted as a kid but couldn't get because of the way it evolves. Alakazam starts out as Abra, and evolves into Kadabra after reaching level 16. Kadabra can then be traded, whereupon it will change into an Alakazam upon arrival. Given the way in which it evolves, it's a wise idea to make friends with someone whom you can trade your Kadabra to with the reasonable expectation of getting it back.
Bug, Dark, Ghost.
One of the original sweepers, is Alakazam. This is one straightforward pokémon, and fairly typical of the psychic-type family: excellent special stats, horrible physical stats. Its Special Attack is enormous and its Special Defense quite good, whiles its HP, Attack, and Defense are all horrible. The only thing keeping Alakazam in most battles is a monumental Speed score, allowing it to outpace most opponents.
What happens when Alakazam transforms into Mega Alakazam? Pretty much what you'd expect, actually - its Special Attack and Speed skyrocket. Everything else, notably on the physical side, remains pitiful. (Though its Defense does jump up a bit. Not enough, though.)
Synchronize: If the pokémon is hit by a status ailment, notably poisoning, paralysis or a burn, the attacker receives the status ailment as well. This is quite handy, as it allows Alakazam to remain first in the turn order if it becomes paralyzed. Burns also don't bother its Special Attack stat.
Inner Focus: This pokémon is immune from flinching. This is somewhat handy if you expect the bad guys to use Fake Out and don't want to lose your turn. Overall, though, not the best ability.
Magic Guard: The pokémon is immune to source of indirect damage, namely burns, poison, Leech Seed, Spikes, and the like. Magic Guard is generally an awesome ability, but I prefer Synchronize because it negates the slowdown caused by paralysis in most cases. Still, if you're a Life Orb fan this is a must-have. Magic Guard is a hidden ability.
Trace: The pokémon copies the ability of the opposing pokémon. This can range from extremely useful (something like Wonder Guard) to utterly useless. Trace is only unlocked when Alakazam changes to Mega Alakazam.
The obvious route to take, and the route most Alakazams will go, is that of a straight sweeper. Regardless of your build, Psychic is the must-have STAB attack. Throw in three more non-STAB special moves and you have your Alakazam. Shadow Ball is your best choice for wiping out dangerous ghost-types, while the other two moves depend entirely on the gaps in your party. Focus Blast, Hyper Beam, Energy Ball, Dazzling Gleam, all are solid choices. I particularly like Dazzling Gleam in this generation for wiping out dark-types that would otherwise make mincemeat of Alakazam.
It's also possible, with the proper EV training, to turn Alakazam into a reasonable special wall. Stick with Psychic, then bolster it with Thunder Wave, Recover, and Calm Mind. So long as your Alakazam isn't exposed to a physical move that gets past its Speed you shouldn't have too much trouble surviving. (That said, I still prefer a sweeper. Alakazam's Speed is just too enormous to waste.)
EV / Super Training
This depends on your build, but the standard Alakazam should focus entirely on Special Attack and Speed. Max out both and toss the remainder EVs, what few there are, into Defense or HP. If you want a special wall instead, shift the points in Speed to Special Defense or HP.
Catching an Alakazam
To get an Alakazam you'll first need an Abra, and beyond that a Kadabra. Abra can be found on Route 5. Unfortunately, the way in which you evolve Kadabra to Alakazam makes it difficult to have the same pokémon from start to finish. You're most likely to get an Alakazam by trading for a Kadabra on the GTS, which requires a net connection. Trying to get one with a level in the teens to maximize your EVs.