Pokemon Tower Defense is 1st generation pokemon only, so no fourth generation or second generation evolutions (including Steelix). Therefore, Onix can't evolve.
you cant
At rock cave
You must Trade Onix while it is holding a Metal Coat in order to Evolve into a Steelix.
Onix evolves into Steelix when it is holding a Metal Coat and traded to someone else.
Onix holding a metal coat,Karablast trade with Shelmet will evolve too.Thats all I know.
the way you can evolve an onix is by letting it hold a metal coat and trading it to a friend and then making them trade it back onix evolves when your trade parterner receives onix.
Nothing.
ptdgames
At rock cave
beat it with a pokemon that has the advantage
In the cave place. I think it is lvl 3.
In Pokemon Yellow Onix does not evolve, it is a one stage Pokemon.
In order to evolve Onix in Pokemon Crater you must beat Cynthia. After beating Cynthia she will give you the mental coat to evolve Onix.
Onix doesn't evolve from anything. It evolves into Steelix, but Onix is the base pokemon for that evolution chain. :)
Trade Onix with the steel coat item to evolve it.
To evolve onix you must give it a metal coat then trade it and it will evolve
There is no Pokémon that evolves into Onix.
It doesnt