HailFall
my cancer is sun and my leo is moon
I began with Ribombee, a new drop with an exceptional speed tier and STAB moonblast. I wanted to build around its specs set.
My next addition was Passimian, which forms a nice core with Ribombee to threaten many of the mons that wall it like Porygon2, Steelvally, and Coalossal. In addition to this, Passimian is a powerful pivot who can force switches and bring Ribombee in safely with U-Turn.
Next I added Rotom-C. It rounds out the offensive core, granting an answer to bulky waters who can otherwise prove problematic such as Vaporeon and Jellicent while also providing defog support if needed to prevent the team from being worn down by entry hazards while spamming momentum generating moves.
The main thing that was missing from the team at this point was a defensive backbone to support it. For this purpose, I added Porygon2 and Fairyvally. Porygon2 can come in on some of the most dangerous special attackers in the tier such as Espeon, Duraludon, and other Ribombee. In exchange, Fairyvally serves as a knock off sponge and answer to many of the Dark and Fighting types that can threaten Porygon. As an added bonus, both of these mons are excellent at generating momentum, resulting in a team overflowing with momentum generation.
My last slot needed to be a rocker, and I needed a check to various mons like Frosmoth, Salazzle, and Braviary. As a result, SpD Coalossal seemed the obvious choice. In addition to checking numerous mons and providing rocks, Coalossal can also use Spikes to further wear down many of Ribombee's checks.
Ribombee
Item: Choice Specs
Ability: Shield Dust
EVs: 252 SpA / 4 SpD / 252 Spe
Nature: Timid
Moonblast / Psychic / Switcheroo / U-turn
Passimian
Item: Choice Scarf
Ability: Defiant
EVs: 252 Atk / 4 Def / 252 Spe
Nature: Jolly
Close Combat / Knock Off / Gunk Shot / U-turn
Rotom-Mow
Item: None
Ability: Levitate
EVs: 252 SpA / 4 SpD / 252 Spe
Nature: Timid
Leaf Storm / Defog / Will-O-Wisp / Volt Switch
Porygon2
Item: Eviolite
Ability: Trace
EVs: 252 HP / 4 SpA / 252 SpD
Nature: Calm
Ice Beam / Toxic / Recover / Teleport
Silvally
Item: Fairy Memory
Ability: RKS System
EVs: 252 Atk / 4 Def / 252 Spe
Nature: Jolly
Multi-Attack / Rock Slide / Swords Dance / U-turn
Coalossal
Item: Heavy-Duty Boots
Ability: Flame Body
EVs: 252 HP / 4 Atk / 252 SpD
Nature: Sassy
Rock Blast / Flamethrower / Spikes / Stealth Rock
Ribombee @ Choice Specs
Ability: Shield Dust
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Moonblast
- Psychic
- Switcheroo
- U-turn
Passimian @ Choice Scarf
Ability: Defiant
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Close Combat
- Knock Off
- Gunk Shot
- U-turn
Rotom-Mow
Ability: Levitate
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Leaf Storm
- Defog
- Will-O-Wisp
- Volt Switch
Porygon2 @ Eviolite
Ability: Trace
EVs: 252 HP / 120 SpD / 136 Spe
Calm Nature
IVs: 0 Atk
- Ice Beam
- Toxic
- Recover
- Teleport
Silvally-Fairy @ Fairy Memory
Ability: RKS System
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Multi-Attack
- Rock Slide
- Swords Dance
- U-turn
Coalossal @ Heavy-Duty Boots
Ability: Flame Body
EVs: 252 HP / 4 Atk / 252 SpD
Sassy Nature
- Rock Blast
- Flamethrower
- Spikes
- Stealth Rock
Ability: Shield Dust
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Moonblast
- Psychic
- Switcheroo
- U-turn
Passimian @ Choice Scarf
Ability: Defiant
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Close Combat
- Knock Off
- Gunk Shot
- U-turn
Rotom-Mow
Ability: Levitate
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Leaf Storm
- Defog
- Will-O-Wisp
- Volt Switch
Porygon2 @ Eviolite
Ability: Trace
EVs: 252 HP / 120 SpD / 136 Spe
Calm Nature
IVs: 0 Atk
- Ice Beam
- Toxic
- Recover
- Teleport
Silvally-Fairy @ Fairy Memory
Ability: RKS System
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Multi-Attack
- Rock Slide
- Swords Dance
- U-turn
Coalossal @ Heavy-Duty Boots
Ability: Flame Body
EVs: 252 HP / 4 Atk / 252 SpD
Sassy Nature
- Rock Blast
- Flamethrower
- Spikes
- Stealth Rock