Taro Urashima, originating from Japanese folklore, enters the *Dr. Slump* narrative through time travel. Arale Norimaki rescues him from drowning during her journey to the past. In gratitude, he presents her with a box; when Senbei Norimaki later opens this box, it causes him to rapidly age. His character design in this appearance reflects Master Roshi from *Dragon Ball*, a character conceptually inspired by the Urashima Taro legend.

In the film *Dr. Slump and Arale-chan: Hoyoyo!! Follow the Rescued Shark...*, Taro Urashima physically appears within an underwater city. He joins Arale in amusement park activities after she and her family are invited by a shark she saved. His attire in this film differs from traditional Japanese fisherman clothing, instead resembling that of a Wild West prospector.