Answer:
Pretty sure it'd be skunks or with skunks.
Explanation:
Frightening is describing the skunks.
What can be inferred based on this description is that many East Egg residents hide their unattractive qualities beneath beautiful, light, and dreamy appearances.
As is the case of Daisy and Tom - they live in a beautiful manor which seems perfect on the outside, just like Daisy and Tom do. However, if you take a peak inside, you will see their true selves - they are unhappily married, Tom is cheating on her with Myrtle, and Daisy is cheating on him with Gatsby.
In this excerpt, the word wonder has a positive connotation.