Summer Ball Zucchini is round, and shaped almost like a small pumpkin.
You can use it in two ways.
When harvested early, around 4 inches (10 cm) wide with bright yellow skin, use it as a zucchini.
Alternatively, you can let it grow to about 2 pounds (1 kg) in weight, with a bright orange skin colour, and use it as a pumpkin / winter squash.
Summer Ball Zucchini can be container grown, though it needs a very large, deep container.
F1 Hybrid.
Sources
Day, Sonia. Attack of the killer zucchini. Toronto Star. 20 August 2009.