Did you mean to add a picture along with this?
What do you mean by what do they hear we need background info
Answer:
Charles feared that the big and scary dog would jump over the short, metal fence.
Explanation:
A comma should be placed between the adjectives that describe the noun <em>fence</em>. The reason is that they are not joined by a coordinating conjunction as in the description about the dog: <em>big and scary dog</em>. As a result, since they appear in the form of list without any linking words, they must be separated by a comma.