Gastornis bird chicks: When you drink water through your trunk, does it taste like boogers?
Ellie: Uh no... Well... Sometimes, Now let's move!
When Scrat removes the giant acorn in Scratlantis the city is immediately flooded. Everyone in the background, including Scrat, is blown away by the sudden rush of water. However, Scrat's host (slightly off-camera) in the foreground doesn't move and doesn't seem affected by the strong flow.
The knife that is given to Louis by the pirates is the exact same knife that Buck had in the previous film.