Here's why:
* Haunter's Evolution: Haunter is the evolved form of Gastly, and Gastly evolves into Haunter at level 25. Then, Haunter evolves into Gengar by using a Trading Stone.
* Trading Stones in Ruby: Pokemon Ruby does not have Trading Stones. This means Haunter cannot evolve into Gengar in this game.
* Haunter Availability: Gastly and Haunter are not available in the wild in Pokemon Ruby. You cannot obtain them through normal gameplay methods.
To obtain Haunter, you would need to:
1. Trade: Get a Haunter from someone who has Pokemon Emerald or FireRed, as those games have Trading Stones.
2. Use a Game Shark or Action Replay: These devices allow you to cheat and obtain Pokemon that are not normally obtainable in the game. However, using these devices may void your game's warranty and may not be considered ethical by some players.
Let me know if you have any other Pokemon questions!