Phagocytosis is the process by which particulate material is endocytosed (“eaten”) by a cell (From Greek phagein, to eat.). The process of phagocytosis is one of the many different ways our immune cells fight infections. Macrophages and neutrophils are cells of the immune system that use phagocytosis to bind and ingest invading microorganisms. Phagocytosis is a complex mechanism that requires for the cells to rearrange its inner cell bits to surround and engulf the target.
Below is a playful animation I created showing a macrophage chasing bacteria to ultimately phagocytose them.
Here is a video of an actual cell under the microscope chasing a bacteria to engulf it. This cell shown is a neutrophil, which are the first cells to get to the site of infection and are ferocious eaters that rapidly engulf invaders.
You can learn more information about phagocytosis here: