It's impossible to definitively say what the "smelliest" object on Earth is, as "smell" is subjective and depends on individual perception. However, some contenders for the title include:

* Durian fruit: Known for its pungent, sulfurous odor, some find it repulsive, while others adore it.

* Stinky cheese: Certain types of cheese like Roquefort or Limburger are known for their strong, often ammonia-like smells.

* Decomposition: Decaying organic matter (like rotting flesh or sewage) produces potent and unpleasant odors.

* Industrial waste: Certain industrial byproducts can have extremely offensive smells, depending on the specific chemicals involved.

* Animals: Some animals, like skunks or certain types of insects, produce extremely strong and unpleasant odors as a defense mechanism.

Ultimately, the "smelliest" object is a matter of personal opinion and sensitivity.