How did they make Violet Beauregaurde Inflate?

In "Willy Wonka & the Chocolate Factory," Violet Beauregarde inflates after chewing an experimental blueberry-flavored gum created by Willy Wonka. The gum is designed to mimic a full three-course meal, but Violet's impulsiveness leads her to chew it before it's fully tested. As a result, she begins to swell up like a giant blueberry, demonstrating the consequences of not following instructions and the dangers of excess. Ultimately, she is taken to be juiced, highlighting the whimsical yet cautionary nature of the story.