The Cyclops Diver (portrayed by Aaron Hendry and voiced by Neil Ross) is a large, male hardhat diver who appeared in The SpongeBob SquarePants Movie and The SpongeBob SquarePants Movie 3 as the tertiary and main antagonist. This air breathing monster never takes off his gear, even on land; possibly because he is too excited about selling knick-knacks or to scare sea creatures for fun.
The anonymous diver owns and works at the dreaded Shell City and is feared by all inhabitants of the sea, mainly because he looks frightening, is gigantic compared to marine animals, captures them, and dries them out under a constantly burning desk lamp in Shell City to dry them out and turn them into "smelly knick-knacks" that he can sell (as seen in the movie). He doesn't have any lines except for evil laughing, humming, "uh-oh," and "huh" when the dead sea creatures came proceeding to beat him up, but mostly you just hear the breathing from inside his helmet.
We first learn of the Cyclops' existence in the beginning of the movie when Mindy first mentioned him while she was warning our protagonists about the hazards of venturing out to Shell City, where Neptune's crown is being withheld. The Cyclops was said to guard Shell City and was described as giant when Mindy classified him as the worst of the hazards.
Later in the movie, just when Dennis and his spiked "big boot" was about to step on SpongeBob and Patrick, we finally see the heinous diver appear, more specifically, the Cyclops Diver's "bigger boot" (as SpongeBob and Patrick call it) step on Dennis in an ironic fashion, saving the duo from Dennis (at the moment), but unfortunately not from the Cyclops himself. Patrick was just about to make a run for it screaming,"Bigger Boot!", when SpongeBob notified him that the hardhat diver's benefactor of a boot had saved their lives. They displayed gratitude towards the pernicious diver for saving them from Dennis, referring to the Cyclops originally as "Stranger", not knowing the Cyclops' true identity at the time. But the Cyclops just stood there, looking for his next victims. Then fear and realization struck SpongeBob and Patrick when the Cyclops looked directly down at them (most likely because he finally heard SpongeBob when he said,"Uhh... Stranger?"), hands ready to grab. SpongeBob and Patrick then discovered that this abnormally large "Stranger", who rescued them from the evil Dennis, was the even more monstrous and giant Cyclops who guards Shell City mentioned in Princess Mindy's warning. SpongeBob and Patrick tried to run away, but with the diver's boots clomping down behind them, failed, and the Cyclops picked them up, gave them a long stare, and proceeded onward, abducting them to the surface. The duo (who recently fainted) were stuffed in a bag, and driven to Shell City in the Cyclops' boat (as shown in script).
The Cyclops then put SpongeBob and Patrick in his glass bowl in Shell City. He then took out a small toolbox SpongeBob referred to as his "evil instruments of torture." He then took glue and google eyes out, and answered SpongeBob's question about what his buiness was with them in front of the duo's glass bowl by making a humorous diorama of "Alexander Clam Bell" out of a dead clam, a play hat, a small rotary phone, and the craft tools he took out of his toolbox. Once he had done this, he then grabbed SpongeBob and Patrick and placed them under his heat lamp so they would dry up and die so he could turn them into smelly knick-knacks. The Cyclops then grabbed a book and went to his restroom. But before their death, SpongeBob and Patrick both shed a single tear which later rolled down the heat lamp's wire and shorted out a power outlet that smoked up causing the fire sprinklers to set off. Having been revived by the ensuing rain, SpongeBob and Patrick retrieve Neptune's crown, but it is picked by the Cyclops. Fortunately, the othersea creatures the Cyclops had killed were also revived and began to beat him up as revenge.
During the scene where the two ride David Hasselhoff, the Cyclops', "bigger boot", emerged from the water with Dennis on the boot's ratel.