Gothitelle
Choice Scarf
Ability: Shadow Tag
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
- Trick
- Torment
- Taunt
- Protect
I've been having a lot of fun with this set recently. There's a couple of things that you're able to do with this set. Firstly, with trick + choice scarf you can lock your opponent into the use of a single move and with shadow tag they're unable to escape. Torment prevents pokemon from using the same move twice in a row, so with trick + torment you're able to force the opponent to struggle, costing them 25% of their health each time. With protect, you're able to protect against the move they are locked into and just alternate between protect + taunt/torment so you only get hit by the struggle damage. With choice scarf you're guaranteed to trap and kill at least one pokemon since it locks them into a single move. The key is to be careful and play mind games as you don't want to switch in on a move that can 2HKO. The pokemon this set is most effective against are typically walls. Pokemon like Chansey/Skarm/Clefable/Ferrothorn/Sylveon/Chesnaught/Suicune/etc. typically only carry a single attacking move and thus fall prey to taunt + torment and so can be trapped and killed without the need of a scarf. Additionally you can run 252 HP / 208 Def / 48 Spe in order to outspeed most Mews and give them a scarf which will hinder their performance throughout the game. Additionally those EVs will allow you to outspeed 0 Spe Skarmory without the scarf. Other things you can switch into are Latios after Draco Meteor, Klefki (which if setting up screens, you can use protect on struggle turns so that screens are gone when klefki dies), or any pokemon choice locked that can't 2OHKO (although you need to have tricked your scarf off to do this).
Due to the pokemon this set works best against as mentioned above, it generally works best on more offensive teams that need certain threats eliminated for a sweep (such as Chansey, Ferro, Skarm, etc.). The EV's can also be altered to fit your needs. If you need to get rid of more threats that are specially oriented then investing into SpD would be more optimal, and in order to outspeed certain threats investing into Spe more. Again this varies from team to team so there is no set spread you should run- it should be spread to fit your team needs. I generally run def because of Ferro/Chesnaught and pokes such as Clefable/Sylveon/Suicune/etc don't hit that hard on the other side of the spectrum unless they already have a couple CMs up and Gothitelle has higher base SpD than Def, although I should probably do some more calculations to get a more optimized spread.
Replay examples:
http://replay.pokemonshowdown.com/ou-192838788
http://replay.pokemonshowdown.com/ou-192859062
I misplayed a little in the second one when staying in on the u-turn but I think it still gets the point across. You just want to avoid getting leech seeded if you're against Ferro/Chesnaught but you can just trick your scarf off beforehand and then switch into them and taunt first to prevent that.