Tiny footlike protrusions that enable a cell to invade neighboring tissues. Scientists first discovered these “invasive feet” popping up on highly metastatic cancer cells grown in the laboratory (shown, yellow). It was thought that invadopodia might help cancer cells burrow into other tissues and eventually spread throughout the body. Despite more than a decade of research on these structures, only recently have invadopodia been found in live animals. A study in C. elegans worms published last year in the Journal of Cell Biology showed that invadopodia form on the uterus of the developing worm and push through to the neighboring vulva, connecting the two reproductive parts. More recent studies have begun to explore how these structures break down the scaffolding between cells to help tumors metastasize.