The Cyclops are recurring antagonists in the Skylanders series.
Skylanders: Spyro's Adventure
The Cyclopses were first seen helping Kaos fight against the Skylanders, only to be defeated. They were later seen in their stone castle guarding the Crystal Eye from the Skylanders, only for them to be defeated by them once again. The Cyclopses would later ally themselves with the Chompies and Spell Punks to fight against the Skylanders and prevent them from obtaining the Eternal Earth Source, only to be defeated again.
Empire of Ice
Some of the Cyclopses seem to have frozen a small valley and built an ice castle onto it, leading to Haldor the Wizard to ask the Skylanders, namely Slam Bam, for help to get rid of them and bring back summer and so did.
Some of the Cyclopses were looking after an old Arkeyan War Machine, believing it to be a type of deity to them. This lead to the Skylanders to bring the Machine Ghost back to original body and fighting against the Cyclopses and also running into Noodles on a few occasions. Some of the Cyclopses have been shown to work for Captain Dreadbeard at Cutthroat Carnival, possibly as security to keep unwanted visitors away. The Cyclopses later returned to work for Kaos after he returned to Skylands, ready to fight against the Skylanders once again. A small group of Cycloses were working for Pipsqueak in a desert town they took over, until the Skylanders destroyed Pipsqueak's bodyguard, a Shadow Duke.
The Cyclopses native to the Cloudbreak Islands went to help Kaos and his forces to 'evilize' the Frosthound and fight against the Skylanders.
Skylanders: Trap Team
Some of the Light Elemental Cyclopses were fighting against the Skylanders, namely Knight Light, to prevent them from freeing Luminous from his prison, although they were defeated.
The Cyclops continued to work for Kaos to fight and defeat the Skylanders. They were later seen on Battlebrawl Island watching the matches unfold.