The illusions used in the film, television, theater, or entertainment industries to simulate the imagined events in a story are traditionally called special effects (a.k.a. SFX, SPFX, or simply FX).
Special effects are traditionally divided into the categories of optical effects and mechanical effects. With the emergence of digital film-making tools a greater distinction between special effects and visual effects has been recognized, with “visual effects” referring to digital post-production and “special effects” referring to on-set mechanical effects and in-camera optical effects.
Since the 1990s, computer generated imagery (CGI) has come to the forefront of special effects technologies.
CGI is used for visual effects because computer generated effects are more controllable than other more physically based processes, such as constructing miniatures for effects shots or hiring extras for crowd scenes, and because it allows the creation of images that would not be feasible using any other technology. It can also allow a single artist to produce content without the use of actors, expensive set pieces, or props.
We are able to almost any CGI effect you can think of. We are limited only by your imagination…