https://www.smogon.com/dex/rs/pokemon/trapinch/
[Overview]
Trapping your opponent is one of the most brutally efficient methods of clearing the path for a sweeper, and Trapinch gets access to the best trapping ability in the game in Arena Trap. Unfortunately, Trapinch is significantly harder to use than its competition in NU, Diglett, due to its much, much, much lower Speed. This rock-bottom Speed of base 10 means Trapinch will likely only make one successful trap in a game, but its monstrous Attack stat compared to Diglett means it can nab a few different KOes the little mole only wishes it could. Trapinch is worth a look into if you're unsatisfied with Diglett, but just be aware it is more specialized and has a higher chance of being deadweight in the wrong matchup.
[SET]
name: It's a Trap(inch)!
move 1: Earthquake
move 2: Rock Slide
move 3: Quick Attack
move 4: Hidden Power Bug / Toxic
item: Choice Band
ability: Arena Trap
nature: Adamant
evs: 252 HP / 252 Atk / 4 Def
[SET COMMENTS]
- You really should not be trapping anything that isn't killed by Earthquake, but the other moves ensure Trapinch has a chance to do something should it need to
- Rock Slide hits most of the things immune to Earthquake for a decent amount of damage
- Quick Attack is actually pretty good chip damage on most of the tier, dealing ~30% to things like CB Hitmonchan, Bellossom, Pidgeot, etc.
- HP Bug worth strong consideration in the last slot for Grass-types, although Trapinch is outsped and nearly OHKOed by all of them unless it gets a Sunny Beamer outside of sun
- Toxic is for bulky Water-types, but again, Trapinch will likely just get outsped and OHKOed
[ADDITIONAL SET COMMENTS]
- Max HP is needed to survive as much as possible and get the kills it needs to. There are very few Pokemon Trapinch can trap if it runs Speed, the most prominent being 0 Speed Sudowoodo, Magcargo, Lairon, Torkoal, and Graveler. But, Trapinch can beat Torkoal, defensive Lairon, and Magcargo regardless, and revenge kill Graveler and Sudowoodo if they're locked into Rock Slide anyway.
- The most prominent Pokemon that Trapinch can trap and kill that Diglett cannot are Sableye and defensive Relicanth, thus these should be your primary targets and focus when teambuilding around Trapinch. Great sweepers that love these Pokemon out of the way are Normal-type attackers like Raticate, Pidgeot, and Vigoroth
- Other Pokemon Trapinch can trap include Swalot, Mawile (although it can just BP out), non-CB Hitmonchan (if at full health), Metang, Lickitung, and enemy Diglett (using Quick Attack)
- Trapinch fulfills a complete support role on the team and should not be relied on to do anything other than trap targets to facilitate a sweep for another, or possibly win a stall war in a stall v stall matchup by removing Sableye. It really should not be considered to be built around, but to be part of a build around another Pokemon or core.
[Other Options]
You really don't want to do anything else here, Trapinch needs the power of Choice Band to get the kills it wants. Soft Sand may allow Trapinch to switch moves and retain a few kills, but the power of Choice Band is what separates Trapinch the most from Diglett
As far as moveset choices go, HP Ghost, HP Flying, and Return are the only things worth consideration
[Checks and Counters]
- Trapinch's goal is trapping, so effectively countering Trapinch is technically impossible. Making a team that is not susceptible to trapping is the first step in not being weak to it
- Using Trapinch as setup bait is the best way to counter its effectiveness, ie. having Calm Mind Chimecho to take advantage of it locked into Earthquake. Other examples include Substitute Pidgeot, Swords Dance Tropius, and Agility Pelipper
- Trapinch is ridiculously slow, so most of the tier is going to be able to revenge kill it, even if they're weak to Ground. Pikachu OHKOes with Surf, 0 Spe Roselia can outspeed even max Jolly Trapinch and OHKO with HP Grass, almost any Water-type OHKOes with Surf
- Just keep in mind that if your opponent switches Trapinch out after a kill that it still has a decently strong Quick Attack in its back pocket, so don't let your sweeper get to too low of health with Trapinch still in the wings