More people are killed by hippos than by any other creature. They are extremely ferocious and terrifyingly agile in water. On land they can be a charging freight train. As mention, hippos are a very skittish creature that would rather attack than run or swim away.
Correction: In Africa, more people are killed by Hippos every year than by any other large animal. Several hundred a year.
However, in Africa, and in the rest of the world, more people are killed by SNAKES (20,000+) every year than by any other critter.
(With credits to Animal Planet)