This might be the most unusually broken thing I have ever come across in my 8-month teambuilding hobby, and I am here to share it with you!
Are you SCARED? (Dunsparce) (M) @ Sitrus Berry
EVs: 252 HP / 4 Def / 252 SpD
- Body Slam
- Baton Pass
Dunsparce is the only pokemon in doubles to be able to Baton Pass max speed in one turn. if you Beat Up Dunsparce with Whimsicott then it gets max speed instantly and then you can BP into one of your designated sweepers. Roost is for healing, Body Slam for STAB and so that you don't get struggle locked when taunted, Baton Pass to pass the boosts, and Coil to boost attack, defense, and accuracy.
Cotton Lord (Whimsicott) (F) @ Focus Sash
EVs: 252 HP / 240 Def / 16 Spe
- Beat Up
I'm pretty sure you all know how Whimsicott works so I'm gonna skip it. It's basically the same set as Beat Up Lucario so just use Beat Up and Tailwind.
Shipwreck (Tapu Fini) @ Sitrus Berry
Ability: Misty Surge
EVs: 248 HP / 104 Def / 124 SpA / 32 SpD
IVs: 0 Atk
- Heal Pulse
- Nature's Madness
Tapu Fini is here to support the sweeper. Heal Pulse to heal teammates, Moonblast for STAB, Nature's Madness to wear down wall into KO range, and Taunt to stop setup and the forever annoying Spore Amoongus and Prankster Whimsicott on the opposing team.
Robin DaBank (Incineroar) (M) @ Misty Seed
EVs: 252 HP / 252 Atk / 4 Spe
- Blaze Kick
- Bulk Up
- Power Trip
Incineroar is actually the sweeper for this team. since were gonna pass max speed to it there is no need to try and put ev's into speed unless you want to outrun Regieleki, which is totally understandable, but you will lose some bulk. Blaze Kick for STAB, Bulk Up to get even more stat boosts, Power Trip for a base 220 power STAB move after one coil, Misty Seed from switching in, and max speed BP from Dunsparce, and that's only one coil, so you can coil even more if you are confident and get even stronger, and Acrobatics, which doubles in power due to the Misty Seed being used, for coverage on Bug, Grass, and Fighting.
Genwunner (Mew) @ Leftovers
EVs: 252 HP / 4 Atk / 252 SpD
- Ally Switch
- Fake Out
- Pollen Puff
Mew is also here to support the designated sweeper. Ally Switch to redirect opposing attacks away from the sweeper, Fake Out for flinching, Pollen Puff to heal your teammates, and Coaching to boost your teammates attack and defense even further.
C418 - Wet Hands (Urshifu-Rapid-Strike) (F) @ Misty Seed
Ability: Unseen Fist
EVs: 252 HP / 252 Atk / 4 SpD
- Close Combat
- Surging Strikes
- Stone Edge
Urshifu is alternate choice for sweeping. If your enemy has strong rock and Water types that would do a lot of damage to Incineroar, then would use Urshifu instead. Acrobatics for coverage on Grass, Bug, and Fighting, Close Combat for STAB, Surging Strikes for STAB, and Stone Edge For coverage on Fire, Flying, Bug, and Ice.
Here's the Pokepaste so you can try the team for yourself.