Development and degradation radiation
Nobita's father is old fashioned, so Nobita uses Doraemon's Progression-Regression Beam to make things as they would have been in the past or future, then starts on living things with a mouse devolved 200,000,000 years to become a large dinosaur and his father evolved into a future man. Remade as The Progression-Regression Beam in the 2005 series.
Aired 10/09/1979EP 139 - Development and degradation radiation
Doraemon
Nobi Nobita is a 4th-grade boy in Tokyo. One day, a round, blue cat-style robot (minus ears) pops up in his desk drawer. Nobita's great-great-grandson (or something) lives in the 22nd Century, but thanks to Nobita's mistakes, the entire family is living in poverty. To rectify this, Nobita's descendent is sent Doraemon back to the past, to help prevent Nobita from making mistakes. Of course this is a difficult task since Nobita is the weakest and least intelligent child in his class. Doraemon does, however, have a 4-dimensional pocket on his front, which contains cool gadgets from the future. With these toys, Doraemon will try to help Nobita. Unfortunately, Nobita also has the bad habit of misusing Doraemon's gadgets and landing himself in yet more trouble?
(Source: AnimeNfo)