"Jack-in-a-box" Natural Recordings by Native Speakers
A jack-in-a-box is a type of toy consisting of a box with a spring-loaded figure of a clown or other character inside. When the box is lifted or opened, the figure suddenly pops out, often with a loud noise and a startling motion, causing surprise and delight, especially in children. The phrase is also sometimes used metaphorically to describe someone or something that bursts into prominence or attention unexpectedly.
Adjacent refers to something that is next to something else, often physically. It can also mean contiguous, meaning sharing a common boundary. For example, "The adjacent rooms were not connected." or "The adjacent offices were separated by a thin wall."