If there's any Pokemon in Little Cup that can make you want to tear your hair out, it's Cottonee. With Prankster and a massive support movepool, Cottonee has everything it needs to annoy its opponents the entire match. It has enough usable moves to play completely different every time you face it, and there's no way to tell what it's running until half of your team has been hit with Leech Seed, paralyzed, or poisoned.
However, that's where Cottonee's positives stop. It's defenses are good but not great for a defensive Pokemon, and with no recovery outside of Leech Seed, it gets worn down easily. It also has no offensive potential whatsoever, sporting awful base attacking stats of 27 and 37 and a shallow offensive movepool to match. Because of this, Cottonee's only sources of damage are entry hazards, Leech Seed, and Toxic. Grass-types are a hard stop to Cottonee as they are all immune to Leech Seed and most (namely, Foongus and Ferroseed) are immune to Toxic. Also, Cottonee has a rather steep learning curve, and it takes some practice to get any use out of it, which can discourage some players from even trying it. Even with all these flaws, you can't help but let out a groan every time this cotton ball shows up in Team Preview.
Don't be fooled by how bare this set looks, as half of its options were left out to keep this concise. Cottonee's stat spread and movepool scream for an Eviolite set, which helps it support its team immensely. Regardless of what you are trying to use Cottonee for, Leech Seed is a must on all of its sets, since this is its only true source of reliable recovery and as such is required to keep Cottonee healthy. Stun Spore works very well on Cottonee and allows it to function as an excellent sand check by switching in on an Earthquake and paralyzing Drilbur. Stun Spore is very, very good, but it can be replaced with Toxic if you are desperate to inflict more damage than Leech Seed does.
Cottonee's other two moveslots are much more customizable. The choice between Substitute and Protect is a big one, as it changes the way Cottonee is played. Substitute can net Cottonee a free turn easily, for example, on a predicted status move or switch, which can spell doom for its opponent. However, a misprediction will cost Cottonee a quarter of its health, which is significant when it has only Leech Seed to keep it healthy. Protect racks up Leech Seed damage on U-turns and helps scout out opposing Choice item users without wasting 25% of Cottonee's health. However, a wrongly-timed Protect can give your opponent a free turn or switch. Encore and Taunt are in the same boat as the first choice. Encore stops setup sweepers trying to set up on Cottonee, as very few of them have priority moves to KO Cottonee with before it can Encore them. Taunt is mainly used to alleviate Cottonee's weakness to hazard setters, especially Grass-types that Cottonee can't harm with Leech Seed, but this is a poor choice for stopping setup sweepers, as they can still attack Cottonee.Team Options & Additional Comments >>>
Cottonee has plenty of other tricks up its grassy sleeves. Memento works very well with setup sweepers, dropping the Attack and Special Attack of its opponents so that the next Pokemon has nothing to fear from them. While its Special Attack stat is pretty miserable, Cottonee could run Hidden Power Fire to roast Ferroseed in conjunction with Taunt, though it is only a 3HKO, and Foongus is entirely unbothered by such a weak attack. Cotton Guard makes Cottonee entirely impregnable on the physical side. As an example, Life Orb Murkrow's Brave Bird, the strongest physical super effective move Cottonee could face, 2HKOes Cottonee a measly 12% of the time without any entry hazards after using Cotton Guard once. Reaching even deeper into Cottonee's movepool, we can come up with Tailwind, Sunny Day, and Switcheroo, but these are usually subpar compared to everything else Cottonee could run. Finally, Knock Off and Endeavor are options that would be amazing if they were not attacks, but since they are, they are poor options better left to other Pokemon.
Checks and Counters
Ferroseed, Foongus, and Shroomish are almost entirely unbothered by Cottonee as they go about setting up their hazards or Substitutes, only "fearing" Taunt. Snover and Lileep are close to being full stops, but despise Stun Spore and Toxic respectively. Murkrow out-Pranksters Cottonee, setting up a Substitute before it can be paralyzed or poisoned or just outright blasting it with Brave Bird. However, as Encore penetrates Substitutes, it can't do much back to Cottonee if it tries to avoid Stun Spore. U-turn is Cottonee's least favorite move, as it breaks Cottonee's Substitutes while also switching the user out, leaving Cottonee vulnerable to attack next turn. Shellder and Dwebble can also get around Substitute with their multi-hit moves, but they won't like taking a sacrificial Stun Spore or having Shell Smash Encored. Abra is immune to all of Cottonee's passive damage, including any hazards, and only really cares about Stun Spore. Deerling is a rare opponent, but nonetheless a dangerous one, as Sap Sipper absorbs pretty much all of Cottonee's moves, boosting its own Attack in the process.