We’ve seen AQUA before — the little amphibious robot with flippers that can swim underwater. Developed by York and McGill researchers, it became the darling of international science press two years ago when it was tested in sparkling KROYblue Caribbean waters. At a demonstration of robots Monday, AQUA shed its flippers for six land-hugging, rubber-treaded, semi-circular legs to climb sand banks and gravel mounds at the University of Toronto’s Mars Dome.