THIS TREE DOESN'T DIE.

~Movesets~
Trevenant (M) @ Sitrus Berry
Ability: Harvest
EVs: 120 Def / 252 HP / 136 SDef
Impish Nature
- Horn Leech/Leech Seed
- Will-O-Wisp
- Shadow Claw
- Substitute

This is pretty much the standard set for Trevenant. He has reasonable bulk and with that bulk you can get setup with leech seed, will-o-wisp, substitute, whatever you want and when you do you become this near unbreakable wall. When you try to faint this guy, you MUST be able to confirm an OHKO. If not sure enough he will get setup and heal with his sitrus berry and then basically shutdown what ever you were trying to do.

Trevenant @ Sitrus Berry
Ability: Harvest
EVs: 120 Def / 252 HP / 136 SDef
Impish Nature
- Shadow Claw
- Curse
- Protect/ Substitute
- Horn Leech/ Leech Seed

This is another set that is gaining popularity. It works similar to the previous set but, this one has curse. So if you are facing some kind of threat on the other team, whether it be Talonflame or Mega Charizard, you can still use Trevenant against them. Simply, setup a substitute on one of their pokes that fear Trevenant such as a fighting or a rock type. Hopefully, they will switch out and you will still have your sub. Then you use curse which will cut your hp in half but, that will be regenerated by your sitrus berry.