Leonard Barnum is the janitor at Teras Elementary School, a job he takes very seriously. He maintains that he keeps the floors of the school clean enough to eat off of, and proves it by regularly doing just that. The school administration tries to discourage this practice, particularly since much of what Leonard eats many other creatures find rather nauseating, but Leonard insists it's a matter of principle. Perhaps the quickest way to earn Leonard's trust and friendship is to join him in a floor meal... if one has the stomach for it.
Leonard is able to suck in liquids through three tubes on his underside and somehow store large quantities of them in some internal pocket, and then to spray them out as needed with a controllable force. He generally uses this to suck up stains and spills and/or to spray cleaning fluids. On occasion he's shown the ability to suck up not just liquids, but solid objects, even some that seem large enough they couldn't possibly fit through the tubes (but they somehow do anyway). The precise limits of Leonard's abilities haven't really been tested.