Chuckorok
Chuckoroks are a species of round, rock-like monsters seen only in Mario & Luigi: Superstar Saga. Chuckoroks have very minor roles in Mario & Luigi: Superstar Saga, and are perhaps most notable for simply being a reference to another game series.
Mario and Luigi encounter Chuckoroks on their search for the Beanstar Pieces, more specifically on their return to Chucklehuck Woods. Here, the Mario Bros. came to a small area inhabited solely by the Winkles, and were eventually forced to enter Winkle Colosseum. Inside the Colosseum, the brothers played a Chuckola Bounce mini-game which finally pitted them against the Chuckoroks, who would move around in a circular motion and spit Chuckola Rocks at Mario and Luigi. Although these rocks would hurt the Mario Bros. on contact, if the pair managed to make the Chuckola Rocks hit their Chuckola Board, they would turn blue and go against their firers. As such, if the rocks now hit a Chuckorok, they would knock the beast away and reward Mario and Luigi with a point. If the brothers caught a Barrier Mushroom, getting hit or manually firing their more-direct barrier at a Chuckorok would also make the creature explode. Although destroying Chuckoroks was a fairly simple feat to pull off, as the Mario Bros. progressed in Chuckola Bounce, Chuckoroks would begin to vary in size; smaller (and therefore harder-to-hit) Chuckoroks would begin to appear.
As these rock-spitting monsters were only given a brief appearance in a simple, rather unremarkable mini-game and were only seen from a somewhat unsatisfying bird's-eye view, not much can be said about the almost mysterious Chuckoroks. However, as stated above, it is very interesting to note that the Chuckoroks are actually a clever reference to the The Legend of Zelda video game series. Specifically, Chuckoroks mirror The Legend of Zelda's Octorok enemies, who, on an unrelated note, actually managed to appear in the Marioverse-related game Super Smash Bros. Melee. Chuckoroks are clear parodies of the Octoroks in that both enemies are circular, angry-eyed enemies who spit rocks out of tubular, Snifit-reminiscent mouths, not to mention that the name "Chuckorok" is even a portmanteau of "Chuckola" and "Octorok". While it is unknown how Chuckoroks move (as they are only seen from above), it can be assumed that they have tentacles, as Octoroks possess these appendages.