The phrase "giant snowball" refers to a large ball made of snow. It is used to describe something that gets bigger and bigger as more things are added to it, like a problem or situation that keeps growing. Full definition
In one place, you'll find yourself rolling giant snowballs into lava to form frozen pathways, and in another, you'll go skating down a long tube in the middle of a level. (superluigibros.com)
Extras include several short films about Goldsworthy (including one about giant snowballs in summer), a lengthy interview with the director, and a photo gallery. (combustiblecelluloid.com)
There are thousands of giant snowballs along the coast of the Gulf of Ob in Siberia. (businessinsider.com)