The Palombisaurus Cemetery Marsupilami houba houba hop! : Season 1 Episode 23

While Hector was on a picnic with his Aunt Diane and the Polombian Chief, he hears Mars calling out and noticed he fell into a hole in a collapsing termite-mount/fireant-hill. The humans join Mars at the bottom, where a tunnel to the more barren parts of Polombia is revealed and, on the other side, they see Mars' discovery: fossils of his mammoth-like forefathers, which Diane appropriately titles Polombiasaurus Hoobah-Hectoris. Hector manages to find a way out of the valley to bring Mars' wife and children, whose playful nature helps him to snap out of it, and get his focus back on the present instead of the past so they can all get back home.