A kind of fodder · also called ensilage

3 views: its portrait, and how it looks in the comparison photos.
About
Silage is fermented green foliage fodder for livestock that weighs about 2.9 ounces (83 g) per cup.
Silage has a typical bulk density of about 22 pounds per cubic foot (0.35 g/mL). Because it consists of chopped, fermented plant foliage with air pockets, it is much less dense than water. It takes up nearly three times the space of an equal weight of water, settling similarly in bulk to loose wood mulch or dried agricultural forage.
From Wikipedia
Silage is fodder made from green foliage crops which have been preserved by fermentation to the point of souring. It is fed to cattle, sheep, and other ruminants.
Read more on Wikipedia →Text from Wikipedia’s “Silage” article, CC BY-SA 4.0.
2 on the site
One cup weighs
2.92 oz (82.8 g)
Quick answer
One US cup of silage weighs about 2.9 ounces (83 g). That makes it roughly as light as a cup of rolled oats.
Typical figures, the same ones every comparison on the site uses; real ones vary.
Compare it
Next to anything: a person, a car, another fodder.