Common Encounters:
* Geodude: The most common encounter, especially in the early game.
* Onix: A sturdy rock-type, encountered quite frequently.
* Machop: A powerful fighting-type that can be a good early-game addition to your team.
Less Common Encounters:
* Graveler: A stronger evolution of Geodude.
* Rhyhorn: A rare encounter, but worth catching for its strong attack and defense.
* Cubone: A Ghost/Ground type that appears in some areas of the tunnel.
Rare Encounters:
* Snorlax: A very rare encounter, and a powerful Pokémon to add to your team. It may only be encountered in one specific spot.
* Chansey: A rare encounter, primarily found in the later stages of the game, after you have defeated the Elite Four.
Tips for Finding Pokémon in the Rock Tunnel:
* Use Repels: Repels will prevent weaker Pokémon from appearing, allowing you to focus on finding the Pokémon you want.
* Utilize the "Sweet Scent" TM: This TM will increase the chance of encountering Pokémon in the area.
* Use the "Super Rod" for fishing: There are rare Pokémon, such as Snorlax, that can be found fishing in specific spots within the Rock Tunnel.
Remember: The rarity of encounters in Pokémon Crystal can be influenced by factors like the time of day, weather conditions, and even your level. So, be patient, and keep exploring the tunnel to find the Pokémon you're seeking!