Falling Rocks are obstacles that appear in the Waterfall section of the Contrabobo level.
Falling Rocks originate from the NES game Contra.
In The Game
Falling Rocks are seen falling in the Waterfall, coming from black holes. Abobo can't attack them, and they don't have a health box. They will kill Abobo instead.
A single falling rock also appears as a object that is vomited out by Kirby when he vomits along with various NES characters if he is defeated in Contrabobo.