Dr. Slump - episode 21 - 26 May, 1998

A super transfer student, Hashimoto, transfers from City Island. All of his classmates never have seen people from city so they are so excited. Senbei promises to take Arale and Gatchan to the amusement park...on the same day Midori offers him tickets to a movie. To solve this problem, Senbei invents Copy-kun to duplicate himself. The problem is, Copy-kun duplicated Senbei’s personality as well. (Source: Wikipedia)