One of the islanders on this island mentions an extremely rare pokemon can be found in Icefall Cave however this is not a legendary pokemon it is a Lapras which you should already have obtained in Silph Co.
Only zubats =)
You can find a rare candy in wayward cave! I already found the rare candy there!
you use a ultra ball
High Leveled versions of Magneton and other obtainable Pokemon from previous areas in the game, but the Pokemon worth mentioning who is obtainable in the cave is Mewtwo.
Articuno ,, in Icefall Cave on Island 4 Rare Pokemon is Lapras but there is only 1% that you will find him
Curilean Cave Mt. Ember/One Island power plant Safoam islands
Tynamo is a rare Pokemon found within Chargestone Cave.
Sneasel is at icefall cave on 4 island but it's extremely rare.
One of the islanders on this island mentions an extremely rare pokemon can be found in Icefall Cave however this is not a legendary pokemon it is a Lapras which you should already have obtained in Silph Co.
A rare Pokemon to get in Wayward Cave and totally worth while in my opinion is Gible. Gible is the 'baby' version of Garchomp.
Rare Pokemon come randomly when you're in the grass or cave.
Mewtwo is in Cerulan Cave but you have to beat the elite four and give bill's friend the two jewels to set up the trading system. Articuno is in the Seafoam Island cave. Zapdos is at the end of the Power Plant. Moltres is at Mt. Ember on Sevii Island 1. If you consider Unown as rare, then go to http://www.gamefaqs.com/portable/gbadvance/file/918916/46239 and Ctrl + F and search for Unown.
its a cave on the battle frontier island i think in emerald. you have to water a sudowwodo and it will attack you and you will battle it. then you can capture it watever. and you i think surf to a cave where only smeargles live. kinda boring other than capturing those two rare pokemon.
If I remember correctly, after you beat the Elite Four, you can catch Mewtwo. Mewtwo can be found at the very end of the cave in Cerulean City. The cave is the one behind the fence, near Nugget Bridge, where the guy was standing in front of the entrace the whole time. After you beat the Elite Four, he moves, allowing you access to the inside -- and poof! Rare pokemon! Strong one, too.
Use dive while surfing and when you find a cave under water enter it and explore the cave and depending on which Pokemon version you have sapphire or ruby depends on which rare Pokemon youll find
in the cerulean cave but it's rare