expression
out of nowhere; as if fallen from the sky or sprung from the ground
Idiomatic expression used when someone or something appears suddenly and unexpectedly, often with a sense of surprise or mystery.
彼は天から降ったか地から湧いたかのように突然現れた。
He appeared suddenly, as if he had fallen from the sky or sprung from the ground.
A set phrase combining the images of falling from heaven and welling up from the earth to express an unexpected appearance.