Now that the third generation of Pokémon is obtainable in Pokémon Go, there’s a new evolution that players are trying to figure out. Wurmple, a common bug-type Pokémon, has two different forms it can evolve into — but no one is quite sure how to force Wurmple to evolve into the one they want.
Wurmple evolves into Silicoon or Cascoon, two cocoon-esque Pokémon that then transform into Beautifly or Dustox, respectively. In its debut games Pokémon Ruby and Sapphire, the form that Wurmple evolves into is based upon an unknown number that defines its personality — which is something beyond the players’ control. Therefore, whether you get a Silicoon or a Cascoon is pretty much random, unlike nearly any other Pokémon in the franchise.
There aren’t personality types or values in Pokémon Go, so this rule doesn’t apply. Players are now trying to figure what influences Wurmple’s evolution in the mobile game, but there’s no consensus just yet.
Some of the theories kicked around have to do with attack and defense stats. Perhaps a Wurmple with better attack power than defensive abilities will become a Cascoon, they suggest? But crowdsourcing by communities like The Silph Road both disproves this notion and is unable to identify anything else more conclusive.
Other data points include how the initial Wurmple is caught, what kind of weather it was captured during, its moveset and what time of day the Wurmple is evolved during. But for the most part, it sounds like players are resigned to the fact that getting a Silicoon or Cascoon could just be as random as it is in the original games.
“It’s funny to me that everyone is so determined to find a pattern or trick when this is the one Pokemon that evolved completely randomly in the games,” wrote one Reddit user. “It’s definitely just RNG in Pokémon Go too.”
Frustrating as this likely is for determined trainers who need to complete their Pokédex (especially because Silicoon and Cascoon aren’t obtainable in the wild), the fact that Wurmple’s evolutionary forms can’t be forced by any method is a key attention to detail. Niantic told us that it looks to the main Pokémon games for guidance in developing and releasing updates, and the randomness of the Wurmple evolutionary tree looks like one of those features borrowed wholesale from Ruby and Sapphire.