????

???? can be a Sharkbone or what appears to be a Blurp with a shark fin attached to its back. They attacked the Mario Bros. while the heroes were in the Gwarhar Lagoon during the events of Mario & Luigi: Superstar Saga. These enemies always appeared in groups that included both Sharkbones and Blurps, so it was impossible to tell which kind would attack until the very last moment of the creature's attack.

The name "Sharkbone" is actually based on beta material and appeared as the undead shark's name in a Nintendo Power guide. This guide also erroneously referred to the Blurp-like fish as "Puffer-Cheep", which was a totally different Cheep-Cheep form encountered underneath Oho Ocean in the Oho Ocean Seabed). Additionally, the German version of Mario and Luigi: Superstar Saga shows "Sand-Cheep" as the skeletal shark's name in coding, but never actually in-game.

Attacks
The ???? has two attacks, depending on which type it is: This combination can be very annoying, since ????s shuffle places each time one of them attacks, making it quite difficult to tell whether an attacker will be above or below Mario or Luigi. Therefore, the Mario Bros. could get hurt by a Blurp type, expecting it to be a Sharkbone, and vice-versa.
 * Sharkbones burrow under and attack Mario or Luigi for large damage and possible Poison.
 * Blurp-like fish will jump right over Mario or Luigi, but if the Mario Bros. jump, they will get hurt.

Trivia

 * Despite some ????s being shark bones, sharks do not have bones in the real world.