"Myxococcus xanthus" is a predatory bacterium that moves on exclusively solid surfaces and exhibits various collective behaviors throughout its lifecycle. In the presence of prey (here E. coli), M. xanthus cells self-organize into periodic bands of traveling waves, termed ripples (left-hand side). In the areas without prey, M. xanthus cells are under nutrient stress and as a result self-organize into haystack-shaped, spore-filled structures termed fruiting bodies (right-hand side, yellow mounds).