From the "Please God Don't Be Fake"files...
from AllExperts.com:
I think that the story of a dwarf bouncing off a trampoline and into the mouth of a yawning hippo is an urban myth and, while a hippo could grab a dwarf in its mouth, decapitate it and could chew on the flesh, it would be unlikely to swallow a dwarf whole, as its throat would not accommodate such a large food item. I can only guess this last piece of information, as I couldn't find any information on the width of a hippo's throat.
Oh Well... notice that the writer called it a "Freak Accident"
Thanks to J. McGlinchy for the link!