Astro Boy: Tetsuwan Atom - episode 30 - 01 Nov, 2003

It has been decided that the Core Raider, a subterranean exploration machine, will be used to explore a huge cavern. In order to back up the system, Atom is hurriedly sent along for the ride. Damon, the captain of the team, is not happy about it. Damon, who says he'll listen to Atom but make the decisions himself, has a strong antipathy toward the robot. Damon does not heed Atom's advice and continues to cut through the dangerous bedrocks. They finally reach the giant cave, avoiding several crises. It is a different world with an unknown ecosystem. Alcard, the sponsor, finds a valuable resource there, the Extra Crystals, and his attitude changes. But the Extra Crystals have a life of their own. They assume a battle formation and surround the members of the expedition. At the same time, giant insect-like monsters attack them. (Source: Wikipedia)