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The Giant puffball (Calvatia gigantea) is a puffball mushroom commonly found in meadows, fields, and deciduous forests worldwide usually in late summer and autumn. Most giant puffballs grow to be 10 to 70 cm in diameter, although occasionally some can reach diameters up to 150 cm and weights of 20 kg. The inside of the mature Giant puffballs is greenish brown, whereas the interior of immature puffballs is white. The large white mushrooms are edible when young. To distinguish giant puffballs from other poisonous species such as Scleroderma areolatum cut them open. Edible puffs will have a white interior. Some similar mushrooms have the white interior but also have the silhouette of a cap-type mushroom on the interior when cut open. These are young cap-type mushrooms and may be poisonous.

Some claim the meat tastes very similar to tofu when cooked. To prepare, remove any brown portions and tough skin if necessary; do not soak in water. Puffballs may be sauteed, broiled, or breaded and fried; they do not dehydrate well, but may be cooked and then frozen.

All members of the true puffball family are considered edible, but be sure to cut the young ones open to make sure there are no gills hidden inside. The deadly amanitas have a volva or "universal veil" that completely envelopes the young mushrooms. Before bursting forth from the volva, they look like little round puffball mushrooms.

Additionally, puffballs resemble the earthball (Scleroderma citrinum). The latter are distinguished by a much firmer, elastic fruiting body, and as an interior that becomes dark purplish-black with white reticulation early in development.

The fruiting body of a puffball mushroom will develop within the period of a few weeks and soon begin to decompose and rot, at which point it should not be consumed. Unlike most mushrooms, all the spores of the giant puffball are created inside the fruiting body; large specimens can easily contain several trillion spores. Spores are yellowish, smooth and 3 to 5 micrometres in size. The dry spores can be used as a coagulant to help stop bleeding.

The classification of this species has been revised in recent years, as the formerly recognised class Gasteromycetes, which included all puffballs, has been found to be polyphyletic. Some authors place the giant puffball and other members of genus Calvatia in order Agaricales. Also, the species has in the past been placed in two other genera, Lycoperdon and Langermannia.