mammoth
Definitions
Any of various large, extinct, elephant-like mammals of the genus Mammuthus, characterized by long, curved tusks and a shaggy coat.
Something of immense size or importance; a giant.
Examples
The museum features a perfectly preserved skeleton of a woolly mammoth.
Building the new bridge was a mammoth task that took over five years to complete.
The company faced a mammoth challenge when trying to expand into the international market.