Question

fix the pronoun error (if one exists). when mufasa cracked open the trunk of magic tricks, they were filled with bunnies and chewed - up hats.

Explanation:

The pronoun 'they' has an unclear antecedent. It should refer to the trunk. So, 'they' should be 'it'.

Answer:

When Mufasa cracked open the trunk of magic tricks, it was filled with bunnies and chewed - up hats.