Review the sentence:
Eric's foot indicated his nervousness during the interview, which jiggled
wildly.
Which jiggled wildly, an adjective clause, is describing interview when its target should be foot. When a modifier is next to a word it doesn't logically describe, it is misplaced.
To fix the problem, you could revise the sentence like this: Eric's wildly jiggling foot indicated his nervousness during the interview.