So I had no idea. When you first hear that fact, you think "Well maybe Reptar roars once and Busta recorded that roar" but it is so much better than that. The first Rugrats movie is all about the babies getting into this Reptar wagon thing that Stu made and going on an adventure. The first time they take the wagon for a spin, it spits a Reptar themed rap written and preformed by Busta hymself.
Isn't that crazy? What possible audience were they appealing to? Children who listened to The Coming? Rap fans who also love Tommy and the gang? It just doesn't make any sense. Watch the video below and decide for yourself what Nick was going for with this strange scene.