Mammoth Squash grows up to 38 inches (96 1/2 cm) across, and up to 30 pounds (13 1/2 kg) in weight.
It has yellow flesh.
Harvest when the squash are 8 inches (20 cm) wide or less. Basically, if you grow it beyond that, count it as an ornamental. The flesh gets watery past that.
100 days from seed.