Bonefins are robotic skeletal fish that appear in Super Mario Galaxy. They resemble Fish Bones but they are more robotic and metallic in appearance. They are minions of the colossal Kingfin and reside below the Bonefin Galaxy's only planet with their leader.
Super Mario Galaxy
Bonefins appear in Super Mario Galaxy in the Bonefin Galaxy. After Kingfin is hit with a Shell, he will summon some Bonefins to aid him in battle. A Bonefin can be defeated by tossing a Shell at one, whenever they see Mario (or Luigi), they will charge directly at him and explode on impact. They don't home in on him and can be destroyed if they crash into a wall or if they reach the surface of the water. After 3 hits, Kingfin will summon heaps of Bonefins to aid him. The Bonefins travel the waters with their leader. After Kingfin's defeat, all the Bonefins disappear.
- In New Super Mario Bros. Wii and onward, Fish Bones behave very similarly to Bonefins but unlike the Bonefins, they don't explode.