Quoted By:
Ludicolo @ Leftovers
Ability: Rain Dish
Level: 50
EVs: 164 HP / 92 Def / 252 SpD
Calm Nature
IVs: 0 Atk
- Rain Dance
- Leech Seed
- Scald
- Giga Drain
Level 50 because you're on cart
HP is divisible by 16, maximising rain and leftovers recovery
Calm because generally Ludi is better as a special wall (plus you'll get a whole 3 free stat points compared to max def Bold) and physical attackers will fear Scald anyway.
Run Energy Ball instead of Giga Drain if you want to get surprise OHKOs on standard Mega Swampert/the occasional OHKO on standard Gastrodon (neither of which will want to switch in on Ludicolo but are pretty popular at the moment)
Honestly though, your best bet is using Swift Swim instead
