One of the most classic recurring sketches in Saturday Night Live history, Chevy Chase's Land Shark character was basically a shark who would coerce its victims into opening their doors by pretending to be plumbers, repairmen or, in this clip, a member of Unicef.
Once the unsuspecting people opened their doors, the Land Shark would eat them whole, making a comment on the ridiculousness of the hysteria over sharks after the release of Jaws.
That's my favorite, but there are sharks for every generation in the list at Ranker. Some text NSFW. Link