come out of the woodwork

Từ điển Oxford Advanced Learner 8th

come/crawl out of the ˈwoodwork idiom
(informal, disapproving)if you say that sb comes/crawls out of the woodwork, you mean that they have suddenly appeared in order to express an opinion or to take advantage of a situation
•When he won the lottery, all sorts of distant relatives came out of the woodwork.
Main entry: ↑woodwork_idiom