Marsupilami S03E23 - The Palombisaurus Cemetery

While Hector was on a picnic with his Aunt Diane and the Palombian 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 Palombia is revealed and, on the other side, they see Mars' discovery: fossils of his mammoth-like forefathers, which Diane appropriately titles Palombiasaurus 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.