Cover photograph: The emerging roles of trogocytosis (cell nibbling) in normal physiology, infection, and disease. In the central nervous system, microglia use trogocytosis to remodel neuronal synapses, and the parasite Naegleria fowleri kills human cells by using trogocytosis. T cells, and other immune cells, take bites out of a variety of different human cells. Bacteria such as Francisella tularensis exploit trogocytosis to spread between human macrophages. Entamoeba histolytica kills human intestinal epithelial cells by performing trogocytosis. Macrophages can perform trogocytosis to kill antibody-opsonized cancer cells. Neutrophils kill Trichomonas vaginalis by using trogocytosis. Primordial germ cells in Caenorhabditis elegans are nibbled by endodermal cells during development. Dictyostelium caveatum kills other Dictyostelium species by performing trogocytosis. (See related article at e00930-19.) (Courtesy of Anita Impagliazzo, reproduced with permission.)