Ash and Misty allowed Brock to study under Professor Ivy while they went on another Pokémon adventure. Over the time of Brock's absence, his character was replaced with Tracey, a Pokémon artist and watcher. Tracey traveled with the team through the Orange League saga. Brock returned after Ash won the Orange League and said that he wanted to join the group again. Ash and Misty asked why he had left Professor Ivy, but once they did, Brock curled up into a ball and said "Don't mention that name..." This was a running gag throughout the next few episodes. It was never determined why he left her, but it can only be assumed that she rejected him and broke his heart like many of the other girls Brock has developed a crush on, though she may have done it more harshly than others.
Ivy trained a Cloyster before Ash, Misty and Brock arrived.