Appearances in Doraemon
I Found a Tsuchinoko! (Mange & Anime)
As Doraemon warns Nobita that Gian is the one who discovers the Tsuchinoko and he gain fame for that, both of them (with Dorami in the anime) travel to the future and bring one Tsuchinoko with them and show off to their friends. But while Doraemon & Nobita will tell their friends upon their discovery (Nobita calling Suneo in the anime), the Tsukinoko escaped from Nobita's house. Both Nobita & Doraemon were finding it until they realized they were too late as Gian is the one who found the Tsuchinoko first.
The Search for Tsuchinoko (1979 series remake of previous episode)
In this episode Nobita goes to search for a Tsuchinoko deep in the mountain and manage to catch it. He however, releases it in frustation as he believes that it was a fake one prepared by Doraemon (which isn't true). After recover the Tsuchinoko, Nobita decides to return it to the mountain where it belongs.
Stand by Me Doraemon
After Doraemon's departure, Suneo said to Nobita that he saw a Tsuchinoko in one of the pipes which Nobita believes. But it was actually a prank for Nobita at April Fools Day.
After the episode aired on 2012, Sekiguchi released Tsuchinoko plushies in limited toy stores & online in Japan. The appearance is similar in the anime. The price ranges from 950 yen to 1,566 yen.