Regieleki

Electric

With the highest base Speed stat in the game at 200, Regieleki can even outspeed boosted Pokemon such as +1 Quiver Dance Volcarona, Choice Scarf Gengar, and Choice Scarf Latios. Its ability Transistor combined with its gargantuan Speed stat, decent Special Attack, high-power Rising Voltage, and Choice Specs makes Regieleki a formidable wallbreaker that can shred apart teams with no Electric-type immunity; even bulky resistant Pokemon and dedicated special walls like Kyurem and Blissey swiftly get 2HKOed. It does well against types like Fighting, Dark, Psychic, and Ghost that have trouble taking on Electric-type attacks. However, Regieleki suffers from having a very sparse movepool that does not include proper coverage moves to hit Ground-types for decent damage and, as a result, is left walled by Ground-type Pokemon. This forces the Regieleki user to think twice before attacking, since a Ground-type Pokemon could switch into it for free. It also has a horrendous bulk, which makes it prone to being KOed by any decent offensive Pokemon, especially priority users such as Bisharp, Dragonite, Rillaboom, and Crawdaunt. Regieleki faces a ton of overlap for improving matchups, as Electric teams are naturally good against types without immunities. It's a niche choice at best due to this.