Caterpie, Metapod and Butterfree (HGSS)

Butterfree is a butterfly-based Pokémon. First it's a little worm, whose becomes a cocoon until reaching this stage, such as in the real world.

Location: Route 30

Stats and evolution
In its Caterpie stage, it has decent Speed and HP. In its Metapod stage, receives a great increase in Defense, though loses Attack and Speed. Finally, after reaching its final stage, it loses a bit Defense, though receives significant increases in its special stats and Speed.

It evolves into Metapod, starting at Level 7, and then Butterfree, starting at Level 10.

Moves, abilities and typing
Caterpie will start off with Tackle and String Shot. It can learn Bug Bite if stays unevolved until Level 15, but isn't too worthwhile since it won't be useful in Butterfree stage, and will make it lose several good moves.

As soon as it evolves into Butterfree, it learns Confusion, which is great, since few Pokémon at this point of the game are able to learn Psychic-type moves. At Level 12, it can learn Stun Spore and Sleep Powder. Stun Spore and Sleep Powder both have 97% accuracy thanks to Compoundeyes. There are pseudo-Thunder Wave and pseudo-Spore respectively. At Level 16, it gets Gust, whose at least early-game is decent. At Level 24, it gets Psybeam, a better version of Confusion. At Level 34, it gets Safeguard, which protect your team from status ailments. It gets its last move Bug Buzz at Level 40, which is its best STAB move.

Its TM compatibility in the major part of the game is quite limited. Shadow Ball and Roost are its only good options, though the latter isn't too recommended since healing up with Hyper Potions is much better. However, losing temporarily its part-Flying can be useful in certain circumstances. In Kanto, it can learn Dream Eater, Psychic, Giga Drain and Energy Ball, and even Air Cutter. Energy Ball can be obtained with 64 Battle Points, while Air Cutter can be obtained with 48 Battle Points.

As mentioned before, Butterfree has Compoundeyes Ability, whose raises accuracy by 30%.

Bug/Flying is one of worst typings in the competitive scene, as it has a double weakness to Rock and is also weak to Flying, Fire, Electric and Ice.

Important battles
Has great matchups against the second and fifth Gyms. Thanks to its Psychic-type moves, Butterfree also can work greatly in the fourth Gym, as well as Koga and Bruno in Elite Four. Bug Buzz is useful against Will, as well as Karen's Umbreon.

In Kanto, has good matchups in Celadon and Saffron Gyms. With Psychic-type moves, it also can be useful in Fuchsia Gym. Can be useful in the entire Elite Four during the rematch, though it doesn't have an advantage against Red except against Venusaur.

Conclusion
Despite being one of typical early-game Bug-types, Butterfree can work perfectly in your team if used correctly.

Rating: 60%.