You get him him somewhere in the tall grass when your about to go inside Victory Road.
You get an ekans and raise it up to be an arbok p.s. ekans are really easy to find!
Using the FireRed Dongle method, in Diamond and Pearl you will find Caterpie, Metapod, Ekans, Arbok, Growlithe, Elekid and Gengar and in Platinum you'll find Caterpie, Metapod, Ekans, Arbok, Growlithe and Gengar.
route 23
You can find it in the Great Marsh with dual slot Firered. Dual slot means you put diamond in slot 1 and Firered in slot 2.
at level 45 by holding a razor dick and leveling its lvl at night for its wet puss-y
arbok doesn't evolve.
you can catch arbok in the great marsh with firered inserted only 8% of time
You can find an Arbok in route 3,4,26,27
Ekans will evolve at level 20.
spell arbok backwards and it spells kobra that's what arbok is do the same with ekans and obviously you will find its a snake
Poison.
She captured it since it was an Ekans. The, it evolved into an Arbok, and later it evolved into a Seviper.