Rocto

Roctos are enemies in Super Mario Galaxy and Super Mario Galaxy 2. They are giant, gray relatives of Octoombas with many pale spots and a blue antenna. They are larger than the Octoombas and their torsos have two large coils, with four cephalopod arms appearing from the bottom. They are capable of firing projectiles from their funnels. They are based off the Octoroks from the The Legend of Zelda franchise, particularly in the 3D games, where they can be defeated by deflecting their projectiles back at them, which is how Roctos are defeated as well.

Super Mario Galaxy
In Super Mario Galaxy, these enemies mostly appear around airships and usually hide in barrels or stand on platforms until Mario approaches them, after which they will try to shoot Mario with coconuts/watermelons or fireballs as their main form of attack. They are always found in pairs. To defeat them, Mario has to send back the coconuts they shoot by spinning. One pair, which shoots only fireballs in the Space Junk Galaxy, must be destroyed by the player throwing shells towards them. Roctos usually guard bridges that will be released upon their defeat. The leader of the Roctos, King Kaliente, is fought twice as a boss.

Super Mario Galaxy 2
In Super Mario Galaxy 2, they reappear in the Shiverburn Galaxy where they act as the final enemy defense before facing Prince Pikante, another boss Rocto. Similarly to the first game, they guard a pathway (of rock over lava) that Mario must use to progress. However, unlike the previous game, they are found in sets of five instead of two. They also appear in the final galaxy, the Grandmaster Galaxy, on the Platform Planet; this is their only appearance where defeating them is not mandatory to progress forwards. They still shoot coconuts and fireballs in this game.

Trivia

 * The data for Super Mario Galaxy contains a model for an unused enemy resembling a cross between Rocto and Electrogoomba under the filename "OtaJack." This fits the theme of Rocto being "OtaRock," King Kaliente being "OtaKing," and the later Prince Pikante being "OtaPrince."