pop up

(noun) a book (usually for children) that contains one or more pages such that a three-dimensional structure rises up when a page is opened. Synonyms: pop-up book, pop-up.

(noun) a short high fly ball. Synonyms: pop fly, pop-fly, pop-up.

(verb) appear suddenly or unexpectedly. Synonyms: crop up, pop up, pop. Examples: "The farm popped into view as we turned the corner." "He suddenly popped up out of nowhere."