Looking for the Tsuchinoko is an episode of Doraemon 1979 anime series. It is based on I Found a Tsuchinoko! with similar premise, but with different plot and ending, thus can be considered a remake of the episode/chapter.
Nobita has to prove his friends of Tsuchinoko's existence after he accidentally says that he had seen the creature.
Suneo invites his friends to his home to showoff a video of a strange object resembling UFO which he recorded the previous night while doing homework, impressing everyone. He then proceeds to tell everyone that this is a proof of UFO's existence, which Gian and Shizuka also agree with. However, Nobita is skeptical about the whole event and proposes that the UFO along with several paranormal incidents may just be a fabrication, and that those are no match to what he had seen. Angry at Nobita's words, Suneo asks about the mystic creature that Nobita claims to have seen, which Nobita hastily replies that it's Tsuchinoko, something that Suneo figures out that Nobita "saw" it from the recent magazine article. After hearing Gian's insult and Shizuka's worry, Nobita replies back that he truly witnessed Tsuchinoko's existence and will be bringing the creature to them as a proof.
Back at home, Nobita begs Doraemon to bring out Tsuchinoko, but Doraemon refuses as even he isn't sure that the creature truly exists. Not wanting to help Nobita and wanting him to learn a lesson, Doraemon leaves Nobita to up his own device and goes watering the flowerbed. Realizing that he has to get the job done by himself a bit, Nobita borrows a "Take-copter" from Doraemon and heads off to the deep forest, believing that Doraemon will help him find Tsuchinoko by himself.
Shortly later, in the deep forest in the faraway mountains, Nobita soon realizes that he is being followed by the worrying Doraemon, but pretends to not notice and walks deeper into the wood. Shortly later, Nobita becomes hungry and Doraemon helps by placing the sandwiches that he made on a tree stump that the former can see. Though satisfied by the lunch, Nobita still hopes for Doraemon to bring out Tsuchinoko, which the latter is adamant in not fulfilling this request. After a long searching, Nobita eventually becomes tired but is ecstatic when he sees a creature moving in the bush. However, Nobita instead encounter a snake and is forced to flee from it. Realizing that perhaps the creature may not exist, Nobita prepares to give up the search only to witness another creature falls down from the tree. Believing the creature to be the Tsuchinoko that Doraemon had prepared for him, Nobita cheerfully smiles, though noting that the creature is more plump that the Tsuchinoko from the magazine, which angers it. Nevertheless, Nobita successfully catches the creature and decides to bring it to Gian, Suneo, and Shizuka as a prove to his previous statement.
At the Open Lot, Nobita reveals the creature to his friends as an evidence to Tsuchinoko's existence. Despite that, Gian and Suneo believe that this is just a robot prepared by Doraemon and leave the place, taking the befuddled Shizuka with them. Thinking that the whole Tsuchinoko's hunt is meaningless, Nobita throws the creature away and heads home, preparing to thank Doraemon for his help but also to slightly complain for not preparing a more realistic Tsuchinoko. This however, surprises Doraemon as the only "help" he gave Nobita was the lunch, causing Nobita to realize that the creature he had caught is the real Tsuchinoko.
Realizing his mistake, Nobita runs back to the Open Lot to find Tsuchinoko, which Doraemon follows to aid. Unable to find the creature, Doraemon scolds Nobita for taking the Tsuchinoko out of its habita and that they must find it as it cannot survive in this environment, which Nobita replies that this happened because he believed Doraemon to be the one who prepared the creature. Before the two can get into further argument, Nobita sees the Tsuchinoko hopping out of the nearby bush and reunites with the creature in joy, impressing Doraemon that Nobita has discovered the mystical creature by his own strength. Doraemon however, is against Nobita showing Tsuchinoko to Gian and Suneo, as it will lead to the mass media discovering about the creature and hunting down them, possibly resulting in Tsuchinoko's extinction, and suggests Nobita to return Tsuchinoko back to its forest instead. Though agreeing with Doraemon's word as he knowing that Tsuchinoko deserves freedom, Nobita pleads Doraemon to at least bring Shizuka with them on this return trip which Doraemon agrees. The two then visit Shizuka and invite her on the trip, and the three head off to Tsuchinoko's forest and returns it back to its home, wishing for it to live happily and have a big happy family. Though Nobita is unable to prove Gian and Suneo about his discovery, he is glad that Doraemon and Shizuka believe in him and are able to see that even he can be true to his own words.