Doraemon (1979)

I Found a Tsuchinoko! (1x132)

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Doraemon warns Nobita that Gian will be the one to discover the Tsuchinoko and gain fame for that, so they both travel to the future to bring one Tsuchinoko with them and show off to their friends. The Tsuchinoko sneaks out to Gian, who makes a name for himself as a result.