Wombats are marsupials and found [only] in Australia, along with most other
marsupials.

A few marsupials (opossums) are found naturally occuring in south America.

Small populations of certain marsupials have been accidentally introduced to
other continents (e.g. wallabies in central UK), although unfortunately for
marsupials most of the artificial introductions have been of plantaceals
into Australasia e.g. rats, dogs, rabbits, camels etc.  These either eat or
displace the natural fauna.

OTOH a Troll can be easily recognised by concocted emaddies, posting way off
topic and silly posts into completely unrelated newsgroups (in this case
alt.autos.bmw) where the only likely interest in animals results from the
effects of collision, or their gnawing the upholstery!