Mismagius

Mismagius is one of the best Pokemon at preserving a team's entry hazards due to its Ghost typing to block Rapid Spin with, access to Taunt to block Defog with, and great Speed stat to ensure it can use the move well. Furthermore, its wide support movepool including Will-O-Wisp, Memento, Thunder Wave, Destiny Bond, and many other options lets it function as an unpredictable and potent stallbreaker on balanced and offensive teams. Its immunities to Ground-, Fighting-, and Normal-type attacks and good special bulk also give it some opportunities to switch in, but its low physical bulk makes it difficult to switch in against most offensive teams outside of Choice-locked attackers. Additionally, while Mismagius outspeeds threatening offensive Pokemon such as Charizard and Jynx, it's quite vulnerable to faster attackers such as Tauros and Archeops, and it strongly dislikes Speed ties with foes such as Scyther, which can OHKO it if they win. Mismagius also usually requires a Colbur Berry to avoid being Pursuit trapped or taken advantage of by Pokemon that use Knock Off as a coverage move, such as Hariyama, meaning it can easily be worn down without passive recovery, especially if it lacks Pain Split. Overall, while Mismagius has a solid Special Attack stat, its best niche over other Ghost-types such as Rotom and Haunter is a support-based set that makes the most of its better Speed tier and movepool, as it lacks the power or secondary STAB to be as offensively threatening as its competition.