Pokemon Episode 5 "Showdown in Pewter City"

The episode begins with ash, misty, and pikachu walking into pewter city when an old man tries to sell them rocks as souvaniers which is pretty sketchy in my opinion.  But regardless Ash takes pikachu to the pokem gym to challange the gym master whose name is Brock.  Brock is a rock pokemon trainer but since ash is a new trainer he doesnt know a whole lot about pokemon advantages and disadvantages.  Brock sends out his onyx while ash sends out pikachu.  Now onyx is a big pokemon and pikachu is a small pokemon so its understandable that pikachu was scared.  Not only was pikachu scared but he was at a disadvantage because hes a electric pokemon while onyx is a rock.  Of course pikachu gets beaten and Misty and Brock give ash an earful.  I dont think anyone with common sence would have givin pikachu a chance to fight because it hasnt had much experiance fighting and its at a huge disadvantage but obviously Ash isnt that smart.  So Ash gets some help super powering pikachu from the sketchy dude that tried to sell them rocks and they return to the gym to fight Brock again.  This time Pikachu, being powered up, defeats not only Onyx but Geodude both of which are rock pokemon. Turns out the sketchy rock dude was Brocks dad who ends up taking over the gym while Brock travels with Misty and Ash in hopes of becoming a Pokemon Breeder.