The Cog would make it's first appearance in w.donkeykong:Donkey Kong Country 3: Dixie Kong's Double Trouble!. It is an item that is required for raising Knautilus and the player has to collect all five Cogs to do so.
The Cog would return in Paper Mario: The Thousand-Year Door on the X-Naut Fortress. It is needed for the prize-grabber crane found on the first sublevel and can be activated by pressing left, right and the middle buttons. It can be found on the top shelf in the room with the Yux experiments. Mario would need to use the vent to reach it.