Xurkitree is such a monster. Welcome to the hardest hitting electric-type in the game (from the special side). Even accounting for Electric Surge, Xurkitree still hits harder with its electric attacks than Tapu Koko (assuming same items, same electric attack, and same investment). And that's prior to Xurkitree getting some additional power through Beast Boost. With access to Zap Cannon, Thunder, Thunderbolt, Discharge, Volt Switch, Shock Wave, Electroweb, and Charge Beam it has all the electric attacks it could ever want. It needs a bit of speed support, but Xurkitree is all about hitting incredibly hard and even the sturdiest of special walls have to be very careful if Xurkitree carries Tail Glow and/or Electrium Z. Although it failed to achieve top 30 spots on the rated battle spot on either singles or doubles, it did manage to get a lot of usage in both the Spooky Cup as a very powerful Toxapex killer and in the Simple Symphony competition as a hard-hitting setup sweeper.
Xurkitree @ Electrium Z / Life Orb / Magnet
Ability: Beast Boost
Modest nature
EVs: 148 HP, 4 Def, 252 Sp.Atk, 4 Sp.Def, 100 Speed
- Thunderbolt
- Discharge
- Dazzling Gleam
- Protect
Doubles Xurkitree for level 50s. You can play around a bit with the speed, moving EVs in between Speed and HP to reach certain speed tiers depending on the speed support you have. If you rely on something like Icy Wind a bit higher speed can be warranted while if you have something like Tailwind or String Shot a bit lower might still be sufficient. Thunderbolt is single-target damage, Discharge is spread damage that 2KOs most foes that do not resist it prior to boosts, and if you get a double KO with it you'll also gain two Sp.Atk boosts at once, Dazzling Gleam is spread damage that doesn't hit your partner and to which nothing is immune, particularly nice to get past certain pokémon like Garchomp, Kommo-o, Latios, and Hydreigon. Xurkitree needs speed support, but if it gets that speed support it can be a very powerful monster, especially once it gains a Beast Boost or two. Electrium Z grants it a powerful nuke in Gigavolt Havoc that OHKOs most unresisting targets unboosted if you really need something gone, and also gives you a way past Minimize Chansey (gain Beast Boosts against Chansey's partners while it sets up Minimize, and then finish it in one go with a boosted Gigavolt Havoc which can't miss). Life Orb is an alternative to boost your power consistently. Magnet gives a bit of a smaller boost and doesn't affect Dazzling Gleam but doesn't hurt Xurkitree's bulk or reveal to the opponent what item it is carrying.
As for doubles partners, Charjabug is one that I personally really like. Charjabug has to Protect when Xurkitree goes for Discharge, but it does provide an extra Battery boost, provides speed support for Xurkitree in the form of String Shot and Electroweb, and has a lot of bulk with an Eviolite.
Suicune is also one that I really like, when you have a Minun to Entrainment Volt Absorb on it. Suicune and Xurkitree have a water + ice + electric damage core together that is only resisted by Shedinja and Volt Absorb Lanturn, and Suicune can also provide speed support with Tailwind.
Mega Sceptile is another pokémon that's fun to use next to it. Sceptile can generally eliminate or sufficiently weaken most Dragon types with Dragon Pulse (so that Xurkitree can finish them off and gain a Beast Boost), and eliminates the likes of Gastrodon and Swampert with Grass attacks. Mega Sceptile also gains boosts as Xurkitree goes for Discharge, although it does prevent Xurkitree from launching Gigavolt Havoc or Thunderbolt. The pair of them do function in an interesting way. Sceptile attacks first and weakens a foe, then Xurkitree follows up with a Discharge for a KO, and then both Sceptile and Xurkitree gain a Sp.Atk boost so they both become scarier for the next turn.
Xurkitree @ Psychium Z
Ability: Beast Boost
Timid / Modest nature
4 HP, 252 Sp.Atk, 252 Speed
- Thunderbolt
- Hypnosis
- Tail Glow
- Energy Ball / Grass Knot
Z-Hypnosis Xurkitree. It's seen quite a bit of usage in singles formats. Essentially you use Z-Hypnosis to gain a speed boost and hopefully put an opponent to sleep. Then, on the switch or enemy sleeping turn, you set up Tail Glow, and then you try to sweep. It's a bit unreliable as Hypnosis's accuracy is shaky, but if it manages to set up it can be quite hard to stop snowballing through an entire team, because at +3 Xurkitree hits incredibly hard, and it'll only gain more power as it picks up KOs.
Xurkitree @ Electrium Z
Ability: Beast Boost
Timid / Modest nature
4 HP, 252 Sp.Atk, 252 Speed
- Thunderbolt
- Electric Terrain
- Dazzling Gleam
- Energy Ball / Grass Knot
Z-Electric Terrain Xurkitree. It doesn't put the enemy to sleep and the boost from Electric Terrain isn't as big as it is from Tail Glow. In a way, it's a slightly lower risk, lower reward alternative to the Z-Hypnosis set, because the advantage is there compared to a Hypnosis miss. When Hypnosis misses, that set only has +1 Speed. Electric Terrain doesn't miss, so you're always effectively at that extra power boost after the first setup turn. And once this set has gained its first Beast Boost it already has sufficient power to KO most opponents. One other advantage of this set is that if necessary, you do have the alternative of going for a Gigavolt Havoc instead of the Z-Electric Terrain.
Xurkitree @ Choice Scarf
Ability: Beast Boost
Timid / Modest nature
4 HP, 252 Sp.Atk, 252 Speed
- Thunderbolt
- Volt Switch
- Dazzling Gleam
- Energy Ball / Grass Knot
If you don't want to risk a setup at all but want immediate fast damage, Scarf Xurkitree is an option, and it's also seen quite a bit of popularity. Volt Switch is worthwhile for scouting and pivoting out while dealing a lot of damage. Thunderbolt is there if you want to stay in and just break stuff, then you can also gain Beast Boosts. The rest is coverage.
