Ludicolo is one of the most essential Rain Dance sweepers because of his Grass typing, which allows him to strike down the annoying Water-type Pokemon who cause havoc for Rain Dance teams. In the rain, he outruns the majority of UU Pokemon and has enough power to slay them with Energy Ball, Surf, and Ice Beam. Ludicolo also has impressive special bulk, enabling him to stay in and set up against a wide range of foes. Lastly, Ludicolo has access to Swords Dance and an adequate physical movepool, which allows him to foil foes who think he's running a special moveset.
However, Ludicolo has a couple of problems. His base 90 Special Attack is not especially impressive, even when using Surf in the rain. Ludicolo can also be picked off easily by a number a priority moves, such as ExtremeSpeed, Fake Out, Quick Attack, and Mach Punch. Even then, Ludicolo stands out as a useful Rain Dance abuser who helps keep the offensive momentum going.
This set aims to sweep through teams once Rain Dance is present. As Ludicolo is usually paired with other Rain Dance sweepers, his main role is to remove Water-type Pokemon who may annoy them.
In the rain, Surf will be the main source of damage. If Ludicolo needs more power, then Hydro Pump is a great alternative. Energy Ball allows Ludicolo to strike down Water-type Pokemon who resist Ludicolo's Water attacks. Ice Beam hits Grass-type Pokemon and Altaria for super effective damage. Surf, Energy Ball, and Ice Beam grant Ludicolo great coverage, leaving the fourth slot open for a support move. Rain Dance lets Ludicolo set up rain to maintain offensive momentum. Hidden Power Psychic OHKOes Toxicroak, while Focus Punch can be used to hit Clefable and Chansey while they recover.Team Options & Additional Comments >>>
While Ludicolo is generally seen as a special sweeper, this set can surprise opponents who switch in their special walls on Ludicolo. With a Swords Dance set up, Ludicolo reaches 524 Attack, which is deadly factoring in rain, which improves Waterfall's damage and Ludicolo's Speed, Life Orb, and great coverage.
Swords Dance is the purpose of this set, allowing Ludicolo to boost his pitiful Attack stat to greater levels. Waterfall gives Ludicolo a strong STAB attack in the rain while also having a 20% chance to flinch lethal targets. Seed Bomb uses Ludicolo's secondary STAB to strike down Water-type Pokemon. Ice Punch rounds the set off by hitting Grass-type Pokemon and Altaria. In the last slot, Ice Punch is generally the preferred option for striking down Grass-types and Altaria, but Zen Headbutt can be used for eliminating Toxicroak while still hitting Venusaur.Team Options & Additional Comments >>>
There aren't many other moves to use other than the ones already mentioned. Synthesis has potential outside of Rain Dance for restoring Life Orb recoil or just healing HP in general. Fake Out could potentially be useful on a Ludicolo who switches out frequently for chip damage, but it won't deal much damage. Icy Wind has its use for lowering the foe's Speed, but Ludicolo will likely already have his Speed boosted via rain. Return on the Swords Dance sweeper could work for overall neutral coverage, but the lack of super effective moves will hinder Ludicolo against specific foes.
A Substitute + Leech Seed combination looks fine at first sight, but it is actually mediocre. Ludicolo will become walled by Grass-types (excluding standard Leafeon or Tangrowth) because his Ice Beam will be weakened as a result of pumping EVs into HP and Special Defense and running a defensive nature. It also doesn't help that Ludicolo takes neutral damage from Grass-type moves.
Checks and Counters
Chansey can switch into a Life Orb rain-boosted Surf without taking too much damage from Ludicolo and Thunder Wave or Toxic him. Then, Chansey can stall out the rain with repeated Softboileds or wear Ludicolo down with Seismic Toss. Clefable can do the same, but she must be wary of switching into Surf or Hydro Pump as it will 2HKO her. Both of these Pokemon must beware of the Swords Dance set, however. Toxicroak is a viable counter to any set without a Psychic-type attack due to his Dry Skin ability and resistance to Grass-type attacks.
Against the Swords Dance set, physically defensive Tangrowth and Leafeon can survive an Ice Punch and threaten back with Sleep Powder or Leaf Blade. Any Hitmontop can threaten physical Ludicolo with either impressive physical bulk and Intimidate or Technician plus Fake Out and Mach Punch. Uxie can usually survive an assault and paralyze Ludicolo with Thunder Wave, but it will end up crippled.
Switching to Pokemon on a predicted attack to outstall the rain is usually the best idea. For example, you can switch in Milotic on a Surf or Ice Beam and then switch to Registeel to take the incoming Energy Ball, and repeat. Doing this also lets Ludicolo take in more Life Orb recoil so you can finally pick it off with a priority move such as Arcanine's ExtremeSpeed, Hitmontop's Mach Punch, or Scyther's Quick Attack. Pokemon already under a Substitute or with Protect are also great at stalling out Ludicolo's rain.
If all else fails, the best strategy is to let your least important Pokemon faint and then switch in the Pokemon who takes the least amount of damage from all of Ludicolo's attacks.