Okay, there were some questions about the Altering Cave, so I'm going to try to clear that up. You can only get one pokemon at a time in the altering cave, the default is Zubat. You can search all you like, but the only pokemon you will find is zubat. Until you connect to a device which will download data into your game (I think the only ones so far were at official nintendo events), and when you connect to it, it randomly changes the pokemon you find in the altering cave to another pokemon. You may get Houndour, Mareep, Smeargle, or any of the other pokemon on the list. All of these pokemon can be caught in both Coloseum and Emerald, so even if you don't find a place to change the altering cave, you still have a chance at getting those rare pokemon.