Searching for an episode

I remember an episode which I believe is from this series, but I cannot figure out which one it is. I have seen it as a very little kid. The chimp had to climb through a tunnel, and in the middle of the tunnel there was a hidden treasure room. When the chimp looks around, a skeleton in the treasure room makes a step or two and collapses. The chimp runs off afraid, later it has to pass the tunnel again and makes a big detour around the bones. Apart from these scenes that treasure room has no importance for the plot. Can anyone tell me which episode this might have been?