Ducks is a verse containing, as the name implies, rubber ducks at almost every space it has that is not filled by another verse or another duck. What the picture is showing is not the verse itself, but one of the ducks contained by the verse if it were put on a small planet in a Universe. It has similar traits to the class-ending Obice Novissimo, but it does not affect the ability of verses to exist in any meaningful way.
The ducks inside of Ducks can be of various shapes (that are usually always duck-like) and their size can range from comparable to a Heck-like verse to as large as the verse that contains it. The ducks are also hollow, allowing them to contain each other or a verse. Unfortunately, some of the ducks have fallen victim to Obice Novissimo-related deletion because their size got too close to it's size.
Some of the ducks are sentient and eat other ducks or smaller(?) verses to sustain themselves. These ducks tend to be benign towards other lifeforms, but they can be very aggressive towards their own kind. If they should get mad at someone, they normally attack with an expansive arsenal of very dangerous weaponry, including sharpened aircraft and garbage disposal combustors. The Wall is often used as a divider to prevent the ducks from actually killing each other.