Xurkitree

Xurkitree, The Glowing Pokémon. One of the mysterious life-forms known as Ultra Beasts. Astonishing electric shocks emanate from its entire body, according to witnesses. It raided a power plant, so people think it energizes itself with electricity. Although it’s alien to this world and a danger here, it’s apparently a common organism in the world where it normally lives. Some of them stand unmoving, like trees, with their arms and legs stuck into the ground.

Overview

With access to the coveted Tail Glow and insane Special Attack, Xurkitree is a Pokémon that one would think would be a top tier threat until you analyze its other stats. 71 base defenses and 83 HP isn't out of the ordinary for an offensive powerhouse, but with its equally underwhelming base 83 Speed this makes things rough as most Pokémon that attack it will either OHKO or deal a lot of damage to Xurkitree. In the end you're looking at a powerhouse nuke with little staying power that is also easy to revenge kill, so Xurkitree ends up being a bit of a one-trick pony with a weird name. This isn't anything to be disappointed with though, Xurkitree ultimately still ends up being a powerful threat when properly utilized as with any Ultra Beast not named Guzzlord.
Positives
High Special Attack - Xurkitree's sky high Special Attack is its major selling point allowing it to just pick up easy KOs when it hits the field or sweep slower teams with little effort due to the combination of Beast Boost and Tail Glow. This also makes Xurkitree difficult to come into due to Electric attackers carrying BoltBeam coverage with Hidden Power Ice, thus hitting everything neutral. It even makes it possible to afford dropping EVs into Xurkitree's bulk since its Special Attack is so high regardless.

Negatives
Low Base Stats - Xurkitree is very similar to Rampardos but better, insane offensive stat and then average stats across the board. This is an issue, especially since access to Tail Glow prevents Xurkitree from staying in lower tier formats as it rips them apart, but its extremely hard to use in standard play with its low Speed and the presence of better Electric options such as Zapdos who brings Defog, Rotom Wash who also brings Defog as well as a Water secondary typing, or Thundurus who has Prankster.

Abilities

Beast Boost - Raises the user's highest stat by one stage when scoring a KO - This just fuels Xurkitree's power as it will always be Special Attack, making it a decent wallbreaker.

Movesets

Wallbreaker

-Thunderbolt
-Hidden Power Ice
-Energy Ball
-Tail Glow
Item Attached: Electrium Z
Ability: Beast Boost
EVs and Nature:
252 SpA /4 SpD /252 Spe
Modest Nature

A bread and butter Xurkitree set, Tail Glow is used when you can get the chance to set up, especially against Stall teams. Thunderbolt is for Xurkitree's STAB option as well as a single powerful hit with Electrium Z. Hidden Power Ice is nice coverage for full neutrality as well as ensuring KOs against Dragons and Landorus Therian. Energy Ball is a nice option for other Ground threats such as the rare Hippowdon and Mega Swampert.

Maximum offensive investment makes Xurkitree as fast and powerful as possible, with a Modest nature boosting its power further. A Timid nature also works though to boost its Speed since Xurkitree hits hard enough anyway, but it does sit at an awkward Speed tier for a Pokémon that can't boost its Speed reliably.

Other Options

Substitute - Using Substitute over Tail Glow is an option as it can allow Xurkitree to stay in on threats that would force it out, but the loss in power and ability to break Stall teams may not be worth it.
Bulky sets - Xurkitree can pull off bulky sets to decent effect since Xurkitree is so powerful that it doesn't need investment to hit things hard after a boost. Investing in bulk makes it possible to set up on more foes and the 50% pinch berries can help almost any Pokmeon's bulk.
Psychium Z - While not a very reliable set, Psychium Z allows Xurkitree to utilize Z-Hypnosis to snag a free Speed boost and possibly a setup opportunity for Tail Glow. However, Hypnosis is known for unreliable accuracy so the set's effectiveness is questionable.

Potential Partners

Volt Switch/U-turn - Xurkitree's low base stats makes it hard for it to find a way in, making a slow Volt Switch/U-turn core a strong option. Rotom Wash is a nice partner due to its ability to handle Landorus Therian, while Zapdos and Mega Scizor can make use of the holes Xurkitree punches in the late game.

Countering Xurkitree

Ferrothorn - Forcing a neutral hit with Hidden Power Ice, Ferrothorn can sponge hits from Xurkitree with relative ease. Ferrothorn can also set up Spikes or Stealth Rocks on Xurkitree when it tries to switch out, but Tail Glow can make Ferrothorn a set up fodder for Xurkitree.

Locations in Games

Red/Blue/Yellow:
Not in game.

Gold/Silver/Crystal:
Not in game.

Ruby/Sapphire/Emerald:
Not in game.

FireRed/LeafGreen:
Not in game

Colosseum/XD:
Not in game.

Diamond/Pearl/Platinum:
Not in game.

HeartGold/SoulSilver:
Not in game.

Black/White:
Not in game.

Black 2/White 2:
Not in game.

X/Y:
Not in game.

Omega Ruby/Alpha Sapphire:
Not in game.

Sun/Moon:
Lush Jungle, Memorial Hill

Ultra Sun/Ultra Moon:
Ultra Plant

Let's Go, Pikachu!/Let's Go, Eevee!:
Not in game.

Animé Appearences

Xurkitree has made an appearance in the anime. In its appearance, one fell out of the Ultra Wormhole and started leeching electricity and ended up in a fireworks-off with Blacephalon.

# -English Episode Name- -Jp. Episode Name- Pics
1021 Twirling with a Bang! Ultra Beast Clash! Operation: Boom Boom Crackle!! Pics
1033 Securing the Future! Connect to the Future! The Legend of the Blinding One!! Pics