Mental Herb
Ludicolo in depth
The rumba and the kappa
The Japanese name, ルンパッパ (Runpappa), joins “rumba” with 河童 (kappa), the river yōkai that carries a dish of water on its head. On Lombre, that dish can still be read as a dish; here it has already stretched into a lily pad the size of a hat. The English name, used as-is in Spain, combines ludicrous or ludic with colocynth, a bitter desert melon. Bulbapedia describes the body as a mix of pineapple and duck, and between the hat, the poncho and the dancing habit, the mariachi reading stands on its own.
Half the Pokédex in TMs and 70 Attack
The list of TMs it can use is huge, and much of it is a trap. Fire Punch, Ice Punch and Thunder Punch with 75 power each, Focus Punch with 150, Hyper Beam, Seed Bomb, Zen Headbutt, Ice Spinner: all physical, and its Attack is 70. Even Swords Dance is there, waiting for someone to fall for it. With 90 Special Attack against those 70, the special route always wins, and the rest of the catalogue is useful for what it is—Substitute, Protect, Encore, Rest and Sleep Talk—which, together with Rain Dish, forms a slow but coherent defensive set.
What is worth taking advantage of is Rain Dance at level 1. It can set up its own weather without relying on anyone, at the cost of a turn; from the next turn onwards, Swift Swim is already active and Hydro Pump hits harder thanks to the rain. In a normal playthrough, that two-turn cycle is enough to sweep Trainer teams, especially with Ice Beam covering the Grass-types that resist both of its types.
Five turns and the place it lost
Before Generation V, this line was the only one with access to Rain Dish. It was in Generation V, with the permanent rain brought by weather-setting abilities, that Swift Swim users became a complete archetype and Ludicolo had its best moment. Since Generation VI, weather created by an ability lasts five turns, just like weather set by Rain Dance, and that change took away exactly what kept it going: five turns to come in, take a hit and fire off two or three attacks are few when its Special Attack stops at 90.
In that same rain, it competes with much more offensively oriented Swift Swim sweepers, Kingdra among them, and the comparison doesn't favour it. What remains uniquely its own is the typing: a Water-type that doesn't fear Electric or Grass, with 100 Special Defense behind it, is a rare resource and still makes sense as an answer to opposing rain teams, where it can switch freely into rival Hydro Pumps thanks to that quarter-damage resistance.
In Scarlet and Violet, there is another way out: Tera Blast appears in its TM list, and Terastallizing lets it change its type to cover Flying, Poison or Bug, the three weaknesses it has carried since 2002. It's the same patch used by half the format, with the difference that it pays off more than usual for Ludicolo, because its two original types are more useful for defense than offense.