One of the new gameplay features in Super Mario 3D World was the Captain Toad levels, where an adventurous Toad explored small, box-shaped levels to collect a number of green stars. These stars were usually hidden and had to be found by manipulating the camera. Toad was also pretty much defenseless; he didn’t have the ability to stomp away his enemies and so had to time his movements to avoid them.
Apparently those short levels were popular, because Nintendo is releasing a game specifically featuring Toad levels. It’s called Captain Toad: Treasure Tracker and will release later this year for Wii U.
Source: Nintendo Digital Event