Equipped with a high speed Choice Scarf processor, this model of Genesect is one of the most dangerous scouting machines in existence! U-turn is key to Genesect's success at wearing down organic beings, allowing Genesect to deal a good amount of damage to the enemy while allowing your army to keep control of the offensive momentum. Even without a Download boost, Genesect can still deal 66.7% - 79.7% to Mewtwo and 83.7% - 100% to Darkrai (a 74% chance to OHKO after Stealth Rock damage). After a Download boost, Genesect's scouting duties become much more dangerous to the opponent, allowing U-turn to OHKO Mewtwo, Latias, and Latios, and also inflicting 52-61% to 4 HP Kyogre, 50-59% to Timid Palkia, 45-53% to Timid Kyurem-W, and 62-74% to max HP Arceus-Grass.
Ice Beam is one of Choice Scarf Genesect's main tools for assassination, allowing it to outspeed and terminate threats that are 4x weak to Ice such as Dragon Dance Rayquaza, Garchomp, Shaymin-S, Gliscor, Salamence, and Landorus. With the power of Download, Genesect's Ice Beam can also severely damage 252 HP Groudon (who takes 64-76%) and 4 HP Zekrom (who takes 70-83%).
While Explosion's power has dwindled this generation, a Download boost will ensure that Genesect's sacrifice won't be in vain, allowing the metallic martyr to vaporize max HP Kyogre, max HP Ho-Oh, Palkia, Reshiram, and Kyurem-W. In emergencies, you can even use Genesect's Extreme Speed resistance to wear down an Arceus with an unboosted Explosion, dealing 49-58% to max HP Arceus and 57-68% to 4 HP Arceus. While Iron Head offers poor coverage, Genesect's hyperalloy skull shatters Kyurem-W after the Download boost, and before the boost, deals 83-98% to Terrakion and 63-75% to Kyurem-B. Iron Head also has a 30% chance of flinching, allowing Genesect to infuriate even the most well-prepared general if Lady Luck is on your side.
If you are willing to give up Explosion or Iron Head, Genesect has two other options to choose from. Flamethrower is Genesect's best chance of hurting most Steel-types in the sun, allowing it to OHKO Forretress, Skarmory, and Scizor (assuming a Download boost), deal 92-100% to Ferrothorn, and 2HKO Excadrill. Be warned though, if your army has rain support, Flamethrower becomes pathetically weak, only being able to 2HKO Forretress and Scizor. The final, most niche choice is X-Scissor. X-Scissor deals less damage to Ghosts, both Kyurem, Terrakion, and has no chance of flinching which usually makes it a less effective weapon than Iron Head, but the extra damage done to Mewtwo, Darkrai, Latias, Kyogre, and Palkia can help Genesect clean through some weakened armies more easily after a boost. One final configuration to note is your Genesect's nature. Naive allows Genesect to take less from physical priority attacks like Extreme Speed, while Hasty allows Genesect to take a bit less from the many powerful special Dragon attacks.
Genesect's Choice Scarf processor and scouting routines with U-turn make it an incredibly independent machine that can work on almost any kind of army, but there are a few things to consider that can make Genesect even more effective than usual. Always try to take advantage of Genesect's common switch-ins, which include Ho-Oh, Lugia, Arceus-Ghost, Giratina, Dialga, and most other Steel-type Pokemon. While checking these Pokemon isn't a bad idea, one of the best ways to take advantage of U-turn is to pair Genesect with powerful, momentum shifting teammates. Choice Scarf and Choice Specs Kyogre are a great example of this, not only setting up rain, but also giving Kyogre the perfect opportunity to unleash a healthy Water Spout depending on the enemy. Choice Kyogre also does a good job of drowning Ho-Oh, Arceus-Ghost, and Forretress. Life Orb Deoxys-A is another example of a great Genesect teammate, using Genesect's U-turn support to patch up its issue with switching in, and letting loose insanely powerful Psycho Boosts. If your army prefers a Pokemon who can take a hit but still offers similar power to Deoxys-A, then Kyurem-W is an excellent alternative. With Choice Specs or Life Orb, almost nothing can switch into Kyurem-W's super powerful Draco Meteors besides Steel-types and Chansey/Blissey, and Fusion Flare and Focus Blast will smash most Steel-types, while Choice Specs can defeat Blissey and Chansey with Focus Blast and hazards support. Choice Specs Kyurem-W is also a good response to most Giratina and Dialga switch-ins after a U-turn. Other Dragon-type Pokemon with powerful Draco Meteors like Rayquaza, Dialga, Palkia, Latios, and Reshiram will also perform a good job of complementing Genesect's U-turn support if Kyurem-W doesn't fit into your team. If your team has sun support, Ho-Oh can be a great soldier to pair with Genesect. Several of the Pokemon Genesect lures in have serious issues with Ho-Oh in the sun (such as Ferrothorn, Dialga, and Arceus-Ghost). Ho-Oh can use Genesect's Fire weaknesses as a great time to switch-in, and thanks to Regenerator and Roost, Ho-Oh can be a great U-turn partner for a longer time than most of Genesect's regular teammates. While Terrakion has issues with Arceus-Ghost and Giratina, it does a great job of smashing through Dialga and Ferrothorn with Close Combat, and ripping Ho-Oh to shreds with Stone Edge. Choice Band Landorus-T can also defeat Dialga, Ferrothorn (if you have Superpower), and Ho-Oh, and can use its own U-turn to form a momentum-keeping partnership with Genesect. Finally, while Darkrai doesn't have the powerful unboosted attacks like the former teammates, Genesect's U-turn support gives Darkrai the perfect opportunity to put a life form to sleep with Dark Void, and it still does a good job of scaring out Giratina, Arceus-Ghost, and Lugia.
Genesect's biggest problem is being worn down by Stealth Rock and Spikes, but ironically Genesect also loves hazards support to make switching out of U-turn more punishing than usual. While Genesect doesn't need Spikes and Rapid Spin support to function, it can make the hyperalloy scout a more effective soldier. Tentacruel is one of the best Rapid Spin users around for Genesect, with a resistance to Genesect's only weakness, Fire. Genesect can also revenge kill some of Tentacruel's problems such as Mewtwo and Latios. While it does share the Fire weakness, Excadrill can use Rapid Spin, offers Stealth Rock, and has the ability to slam Dialga with a STAB Earthquake. Forretress can provide Genesect with Rapid Spin and Spikes support to punish your enemy for switching out, and even has access to Volt Switch to keep momentum on your army's side. If you just need a Spiker, then Ferrothorn, Skarmory, Deoxys-S, and Deoxys-A are still fine choices if your army doesn't need Rapid Spin support. While a more risky option than spinning, Genesect can be paired with one of the two Magic Bounce users, Espeon or Xatu, to take care of hazards. Another option for extending Genesect's warranty is to pair it with the viable Wish users of Ubers: Chansey, Blissey, and Jirachi. One final thing to note is that if your team deals with entry hazards and has Drought support, Ho-Oh is an even greater teammate than usual!