Final answer:
The author might use the goldfish as a magical being archetype to develop the events of the story and Sergei's character by adding an element of fantasy, driving the plot and creating conflicts, and symbolizing transformation or personal growth.
Step-by-step explanation:
The author might use the goldfish as an example of a magical being archetype to develop the events of the story and Sergei's character for several reasons. First, the presence of a magical being adds an element of fantasy and wonder to the story, engaging the reader and making it more interesting. Second, the goldfish's magical abilities can drive the plot and create conflicts, as Sergei may have to make choices or face challenges related to the goldfish's powers. Finally, the goldfish archetype can also symbolize the theme of transformation or personal growth, as Sergei learns important lessons or undergoes changes through his interactions with the goldfish.