Sergeant Sam Roderick (Mr. Sharky) is a character that played a big part in the episode: Mrs. Puff, You're Fired. Sam took over Mrs. Puff's job because she got fired by her boss. He is a very strict shark that was once in the navy. He maybe could have been a guest on the show.
He made SpongeBob do a number of things before he started to drive. Then SpongeBob got into the car and he told SpongeBob to put a blindfold on. So he taught SpongeBob to drive while blindfolded. However, he was powerless because SpongeBob still remains without a license and Sam Roderick leaves and does not care. When he walked into the classroom, he made some rules and points which intimidated the class and caused them to leave. Obviously, SpongeBob was still there.
He also offered bonbons to the class, someone took one, and was thrown out of the classroom (literally). He has the overall talent of a very good sergeant and navy leader. The sergeant has only ever been seen in this episode and unfortunately he has and probably will never be seen again. It is quite possible though that he could be seen as a cameo in a possible war episode that could be created sometime. Also, he loves his wife, and he is married. It could be possible that he could be dead after being ran over by SpongeBob in his unsuccessful attempt to stop the boat. He is voiced by Robin Sachs.
Sergeant Sam Roderick is a shark with average looks like a sergeant instructor. He has a small hat, a green army top and various badges and gizmos. His physique is very good, he is skinny, has many muscles, and he is quite tall for a living creature. He also has a very large nose. He speaks with an Australian (not English) accent. He is to be kind of mean to his students.