analysis of a minor chaarcter in in harry potter first book (500 words!)

For this forum, please select one of the minor characters in the novel and describe that character's significance to the novel's tone and meaning.  (Please do not select Harry, Ron or Hermoine!)

Use examples of dialogue and action from specific scenes throughout the novel to support your ideas.  Although your choice may not be a "major" hero or a "major" archetype such as Harry, Ron or Hermoine, explain and justify the importance this character has in the novel.