Kirby becomes a single pink piece of string with a red knot at one end, while Prince Fluff becomes a single blue string with an orange knot at one end. Their faces are visible at the other end of the strings.
With this form, Kirby and Prince Fluff can squeeze through small tunnels by pressing the +Control Pad. The two can then move along the tunnel by pressing the +Control Pad in the corresponding direction. Yarn balls would not fit through the opening, and will be automatically dropped if Kirby or the Prince enters this form while carrying one.