Bananawani are giant crocodiles with banana-shaped growths on their heads. They are so fierce that they even prey on Sea Kings and are to date the Sea Kings only known natural predator. Despite their strength they were easily defeated by Sanji. They first appeared in Chapter 127 and Episode 77. They are classified as type "C" creatures being "Big Savage". Bananawani is a portmanteau of the Japanese word "wani" (which means alligator or crocodile) and the English word "banana". "Bananawani" is also the name of a Japanese park, where people can see plants, crocodiles and turtles.
Crocodile had many Bananawani as pets in his old casino that got destroyed in Rainbase. He could control them as they were often seen in the room with him and Nico Robin without any sort of aggressive attitude toward either of them. Crocodile seems to have had them well-trained as they would also follow his commands, such as eating Mr. 3 and the key he dropped into their den merely by looking at one. Their stomach acid is resisted by Mr. 3's wax.
The is a type of Bananawani that is less ferocious than his counterparts and goes very fast in the Sandora Desert. It lives in Alabasta. Unlike their larger cousins, they have two banana-shaped growths, one on their tail and one on their nose. Miss All Sunday once used this type of animal in Chapter 180. Its name, speed, and the location of its banana-shaped growths are inspired by the F-1 racing car.