You just beat Brawly in Dewford Town, now we have to head all the way to Mauville City. Mr. Briney will take you to Slateport City if you go and talk to him. In Slapteport City you will see a lot of merchants and what not. You will also run into a museum on marine related things like boats and submarines. You will have a bit of a walk to do to get to Mauville City when your done running around in Slateport City. Mauville City has a lot of things, it has the box shop and the game corner for starters. The daycare is also nearby. Once your finished walking around you can head on over to the gym. This gym is sat up matching the element of the gym, electric type. You will have to fight several trainers, they will mainly have Plusle and Minun, Electrike, and Voltorb. Just the regular electric type Pokemon you will encounter.
Watson is the gym leader, he is a jolly old man. I suggest you bring some Paralyze Heals or some Cheri Berries which cure paralyzed Pokemon. When the battle starts Watson will send out a Voltroc at level twenty. Don’t let it use Rollout too many times, it also knows Self destruct so be prepared for anything. It also knows Shock Wave which is an alright electric attack, it can do some damage. If you manage to take out the Voltrob Watson will send out a Magneton. Magneton is the evolved form of Magnemite. Be ready for a powerful battle, this Magneton knows Thunder Wave that can paralyze your Pokemon, look out for that attack. It also knows Supersonic which can confuse your Pokemon. It is pretty tough to attack if your Pokemon is paralyzed and confused. It also knows Sonic Boom which does about twenty damage or so.
Magneton also knows Shock Wave, as said above a pretty decent electric type attack. Next Watson will send out an Electrike at level twenty. It also knows Shock Wave, don’t let it use Howl too many times or it’s attack stat can get pretty threatening. It also knows Leer which can lower your Pokemon’s defense. It should be easy to take it down. He will send out his strongest, a Manectric. It is the evolved form of Electrike and holds a Sitrus Berry which can restore it’s health if it gets too low. Manectric knows all the attacks Electrike knows except instead of leer it has Thunder Wave. If you beat it you will get the Dynamo Badge and TM Shock Wave.