Sounds likeraynboots: an ankle-high overshoe of rubber or plastic for wear in rain and mud.
Rain boots are made for mud, rain, seawater, sand, and anything else you can think of to throw at 'em. The classic rain boot design is completely waterproof and effectively protects your feet and the lower portion of your legs from being soaked by the rain, mud, and sleet among a variety of other conditions.
While usually called rubber boots, but sometimes galoshes, mud boots, rain boots, mucking boots, or billy boots, in the United States, the terms "gumboots", "wellies", "wellingtons", and "rainboots" are preferred in Canada.
NOW go outside and excitedly splash in puddles and catch rain drops on your tongues!