During Nintendo Direct's special E3 video, President Iwata revealed the next installment of the Mario Kart series titled Mario Kart 8. Not only will it have the aquatic and glider transformations from Mario Kart 7, but it will include a new anti-gravity form.
This new anti-gravity transformation has your vehicle's wheel positions change to where they are flat facing the road. As it takes on this new shape, energy radiates from the wheels creating the anti-gravity effect. From the gameplay shown, this will allow players to race both on walls and on the underside of the track. Mario Kart 8 also promises greater integration of the Miiverse.
Mario Kart 8 releases exclusively for the Wii U in Spring of 2014.
Source: Nintendo Direct