Entosis is a cell-in-cell formation mechanism that targets viable cells for uptake in epithelial cell cultures and human tumors. Entotic cells control their own engulfment, by invading into their hosts in a Rho-GTPase and actomyosin-dependent manner. Although entotic cells are internalized while alive, most eventually undergo a non-apoptotic form of cell death, called entotic cell death, that is executed non-cell-autonomously by autophagy proteins and lysosomes. Here we review the current understanding of entosis and entotic cell death and discuss the potential roles of this process in cancer.