Kurt Auffenberg mentions one of the ugly creations of mother nature, Bufo
marinus, also known as the cane toad.
 
After having shovelled loads of them out of my laundry, I can assure they
are a pest anywhere in the tropics, not because they were in my laundry,
but because they are poisonous. They have poisonous glands on the back of
the head, and poison will squirt through the skin if the toad is in
distress (i.e. if you try to pick it up). This poison is deadly to any
(native) animals who eats it and is responsible for a large number of
deaths of the native fauna (as well as displacing them in their habitat).
These animals are a serious pest!
 
Also, they are not from Africa at all, they are natives of south America.
 
Patty