Make a fakemon, give them stats, typing, abilties and a moveset.
Im shit with names so im skipping naming.
Dark/Psychic
Ability: Trickster
Sets up trick room upon entry
HP:80
Attack: 60
Defense: 85
Sp. Attack: 90
Sp. Def 95
Speed: 110
Moves: Calm Mind, Dark Pulse, Psychic, Shadow Ball, Aura Sphere, Nasty Plot, Parting Shot, Recover, Screens, Will-O-Wisp, Taunt
It has high speed so it can "slow" parting shot into defensive pivots or slow sweepers. Pretty versatile, would fit nicely on OU niche trick room teams with stuff like mega mawile. Essentially a support pokemon but can run offensive calm mind sets (Granted you're slower than base 111+ speed mons)

Standard Trick Room lead:

Hexnya @ Leftovers
Ability: Trickster
EVs: 252 HP / 252 SpD / 4 Def
Calm Nature
-Taunt
-Parting Shot
-Recover
-Psychic / Foul Play / Icy Wind