Arguably the most underrated Ghost type in NU, Haunter acts as a means to pressure the balanced & bulkier teams that are really common in the tier. This pokemon has little to no switch ins, which makes it very dangerous as long as it's able to get free switch ins. The main counter to Haunter is Skuntank because it resists both Haunters STABs. This is where Reflect Type comes into play. You copy Skuntank's typing so you don't get trapped. HP Ground also allows Haunter to 2HKO Skuntank with ease.

Haunter is a glass cannon, so Volt Turn core makes sure it can get in safely. You can attempt to bring it in against fairy types, which usually cant do much damages to it, though. Timid is essential as Haunter can get a free hit vs Mesprit which usually gets outsped and OHKod by Haunter, and we all know how important that is considering how popular Mesprit is. While Haunter works better versus bulky teams, it's not dead weight versus offensive teams. Even though it won't switch into much, it can still revenge kill things like Liligant, Mesprit, and basically anything that is slower and has already taken prior damage.