Butterfree

Compoundeyes
Increases this Pokémon's accuracy by 30% and increases the chance of finding items on wild Pokémon.
Type Tier
Bug / Flying NU
Statistics
Min- Min Max Max+
HP
60
- 261 324 -
Atk
45
113 126 189 207
Def
50
122 136 199 218
SpA
80
176 196 259 284
SpD
80
176 196 259 284
Spe
70
158 176 239 262
Name Item Nature

Double Status

Leftovers Timid / Hasty / Naive
Moveset EVs
~ Sleep Powder
~ Stun Spore
~ U-turn
~ Bug Buzz / Hidden Power Ice / Hidden Power Fire
4 Def / 252 SpA / 252 Spe

Compoundeyes increases the accuracy of both Sleep Powder and Stun Spore to 97.5%, which is only the reason to even use Butterfree. Double powder is a simple strategy: Sleep Powder something the first turn and catch whatever switches in with Stun Spore. U-turn allows Butterfree to escape a paralyzed / sleeping opponent, and is a good STAB move to have. The last slot is mainly filler—Bug Buzz is a decent special STAB move, Hidden Power Ice helps Butterfree deal with threats like Gliscor and Salamence if you plan on using it in OU, but Hidden Power Fire does decent damage to Steel-types. The last two slots are good places to put other support moves like Sunny Day. If you aren't using U-turn, use Timid over Hasty; same goes for Jolly if you aren't using a special move.

Other Options

Butterfree's movepool isn't huge, and it can't use many of the options presented to it because of its poor defenses. Skill Swap can be a good move in double battles, and if you're playing in an environment where Double Team is allowed, use it. Choice Scarf is a valuable option, as a fast sleep is always good. Focus Sash can also give Butterfree a chance to sleep a faster opponent, though Stealth Rock / sandstorm can undermine that effort easily. Butterfree can also change the weather to support its teammates. Don't even bother with Roost, as that would hardly increase Butterfree's poor durability at all. Tailwind can be used for team support.

EVs

Butterfree needs maximum Speed—it's only going to spread status, and it needs to be fast to do so. Otherwise, pump the attack stat you see yourself using the most; Butterfree takes hits like a wet paper bag anyway. Make sure that Butterfree's HP ends up being an odd number, to stop Butterfree from fainting on the second switch in with Stealth Rock, rather than surviving with 1 HP.

If Butterfree is using U-turn instead of Bug Buzz, it will need to use more Attack EVs.

Opinion

Stealth Rock really did seal Butterfree's fate this generation. Butterfree cannot afford to take 50% damage with its defenses. It did gain things like U-turn and Bug Buzz, which both add to its offensive movepool, as well as support options like Tailwind and Roost. Sunny Day can aid in Butterfree's attempt to support the team. Butterfree's biggest selling point is its accurate Sleep Powder, and should be played to abuse it.

Counters

Anything that can absorb Butterfree's double status is a counter, as that's the best that Butterfree can do. Guts / Quick Feet users, like Ursaring (Mightyena in NU), can take both statuses and use it to their advantage. Anything using Sleep Talk, Insomnia, Natural Cure and other moves / abilities that handle status can also take on Butterfree. Usually, any Pokémon that is faster than Butterfree can kill it easily.