
https://www.smogon.com/dex/rs/pokemon/castform/
[Overview]
Huntail, Bellossom, and Tangela are some of the most potent sweepers in NU, and Castform happens to be able to check them all offensively, something very few other Pokemon can accomplish. Being able to take advantage of any weather is a cool niche and Castform's special attacking movepool is about as good as it gets, but the rest of Castform is pretty lackluster. Its stats are just too low to attempt a weather-based sweep, which is what it really wants to be able to do. You should really only bring Castform if you are using an offense team and you are sure your opponent is going to bring a weather sweeper. Otherwise you're probably better off bringing something like Kecleon.
[SET]
name: Special Attacker
move 1: Thunderbolt
move 2: Weather Ball / Fire Blast
move 3: Thunder Wave
move 4: Substitute / Hail
item: Leftovers / Lum Berry
ability: Forecast
nature: Timid
evs: 4 HP / 252 SpA / 252 Spe
[SET COMMENTS]
- Thunderbolt + Weather Ball nails the three prominent weather sweepers and has pretty good two-move coverage in any weather
- Weather Ball a bit more flexible in its use, becomes a base 100 STAB Water move in rain which helps prevent Castform from being walled, Fire in sun, Ice in hail, Rock in sandstorm
- However, Weather Ball contingent on weather being active to be useful
- Fire Blast non-weather contingent and Castform's strongest reliable special attack
- TWave helps Castform be useful outside checking weather sweepers and is Castform's best option against a full health Huntail
- Hail messes up weather supporters and allows Castform to inflict passive damage for a few turns
- Substitute protects Castform from the switch-in and makes predicting easier
[ADDITIONAL SET COMMENTS]
- Modest + Thunder can be used to ensure OHKO against Huntail. Thunder sucks outside rain though, and Timid is wanted to outrun Timid Tangela before sun is set up or hit by Sleep Powder
- Lum Berry can ensure Castform is able to check the sun sweepers without fear of Sleep Powder connecting
- Castform really only fits offense teams that need a faster weather check than something like Kecleon.
- Main thing to remember is that Castform is only a check to Huntail, can't switch into Hydro Pump followed by HP Grass and doesn't KO with Thunderbolt or Timid Thunder half the time
[Other Options]
- Sunny Day + Solar Beam, Rain Dance + Thunder, Hail + Blizzard
- Physical set w/ Sandstorm
- Body Slam, Icy Wind
- Future Sight
- Thief, Toxic
[Checks and Counters]
- Anything with good special bulk not weak to Thunderbolt or Fire Blast; Flareon, Torkoal, Whiscash, Lickitung, Kecleon
- Anything faster with decent power; Hitmonchan, Pidgeot, Raticate