The Off-Roader is a form that Kirby and Prince Fluff can take on in Kirby's Epic Yarn. It is not an automatic transformation, nor a transformation that can be taken on anywhere. It can only be taken on if a certain Metamortex is jumped into.
The Off-Roader is basically a monster truck form of Kirby (or Prince Fluff), and therefore can do many things a monster truck does. It goes very fast on land, and is one of the fastest of the transformations, and it can jump quite high, to get to higher platforms that lead to treasures, only by pressing "2". There are other Metamortexes along the track that can make the two go even faster, and allow them to plow through rocks.
When the player gets to control an Off-Roader he will usually have to race Monster Buggies (enemies in monster trucks). Coming in first is not necessary, but add even more fun and challenge to the level. Coming in third place or higher gets the player coins as well, the higher the place the more the coins.
The Off-Roader looks like a miniature monster truck, which is what it is. Kirby appears as a pink truck with black tires and spoiler. If a second player is there as well, the spoiler is replaced by a rocket engine.