Hot Cogs is the third level of Peach's Castle in New Super Luigi U.
The player starts in a lava cave with a Cog turning clockwise, and a Podoboo is jumping around the gear. A ? Block containing a power-up is found, and is followed by another gear and Podoboo. A section of the ground is found, and a Goombrat is found on it. Another Goombrat is found, along with a row of Podoboos below a row of Brick Blocks with a Red Ring above them. Another section of gears follows, with more sideways-jumping Podoboos found. Another section of the ground follows, along with a Goombrat and some Podoboos. Six more gears and some Podoboos are found in the section leading to the Goal Pole.
- Star Coin 1: At the very first gear, the player must wait for it to rotate a bit to reveal the first Star Coin.
- Star Coin 2: After the second gear, the player must head to the area below the arrow sign and continue moving right. The Star Coin is located over a gear, almost completely submerged in lava.
- Star Coin 3: The player must have an Ice Flower. Then, when they player encounters the third Goombrat, they must use Ice balls to defeat the Podoboos, accessing the Star Coin.
- When Luigi reaches an arrow sign, he must break the hidden Brick Blocks to reveal a crouching 8-bit Luigi.