What does the overhead shark special effect mean?

The overhead shark effect is a special effect, which usually appears in movies or TV series. According to the public information related to the query, this special effect is generally realized by computer-generated image technology. Specifically, when making a scene, the photographer will shoot the characters on the spot, and then fuse these shots with the shark images generated by the computer, so that the characters in the picture seem to have a shark floating above their heads, thus creating a tense and exciting atmosphere.