Rejected numbers: 583 (Vanillish)
Smogon official tier: NU
Base Stats: 50 HP, 50 Atk, 150 Def, 50 Sp.Atk, 150 Sp.Def, 50 Speed
Abilities: Clear Body, Sturdy (HA)
Usable moves: Calm Mind, Dazzling Gleam, Explosion, Façade, Flail, Frustration, Gyro Ball, Hidden Power (Electric, Fighting, Fire, Grass, Ice), Light Screen, Moonblast, Nature Power, Protect, Psychic, Reflect, Rest, Return, Rock Polish, Rock Slide, Sharpen, Sleep Talk, Stealth Rock, Stone Edge, Substitute, Sunny Day, Toxic, Trick Room
Not listed but notable: Power Gem
Three words: nothing but utility. Stealth Rock, Trick Room, dual screens, Toxic…that’s pretty much all of Carbink’s usable options. Due to its laughable base 50 offenses, its sluggish base 50 Speed, and its limited movepool, it has no chance of being offensive in any way. Also, due to its typing rendering it weak to common types in Water, Grass, and Ground (as well as 4x weak to Steel, a less common type), as well as its lack of reliable recovery, it has little hope of becoming a wall either (although fortunately, despite its weaknesses, it has Sturdy to guarantee survival of any one hit). Therefore, there is no use for Carbink other than its utility.
Carbink @ Mental Herb
EVs: 252 HP / 4 Atk / 252 SpD
IVs: 0 Spe
– Trick Room
– Stealth Rock
To any Trick Room team that needs a lead, Carbink works. The item Mental Herb prevents it from being Taunted so it has at least one (or two, depending what turn you use Trick Room) opportunity to use its precious utility options. Toxic is there to wear down anything not immune (but really as filler more than anything), while Explosion exists 1) in case of being Taunted twice, and 2) to deal (pretty weak) damage and offer a free switch to a slow offensive threat like Rampardos or Camerupt.
Light Screen and Reflect are its only real other options. These two moves can be placed over Toxic and one of Stealth Rock or Trick Room depending on your team’s needs. (If placed over Trick Room, no need for a -speed nature.) Everything else is outclassed.
Keep in mind that this team was built with pre-ORAS concepts in mind, but I think Showdown has gone full ORAS now.