After Didi has hided the cookie jar from Angelica, Angelica has threatened the Rugrats with her starvation if they don't find the cookies in time. Their mission becomes a prehistoric fantasy, where the Rugrats, now ""cavebabies"", find Dil, the ""Wise Cave Baby"", so he can point them in the direction of the cookie jar, or, ""Cookiesaurus"".
Casts:
Elizabeth Daily, Kath Soucie, Cheryl Chase, Dionne Quan, Tara Strong, Joe Alaskey, Melanie Chartoff, Tress MacNeille, Jack Riley, Cree Summer, Nancy Cartwright