Bug's Life, A Easter Egg - Secret Level

First, go to the trainning level and complete all the challenges until you get to the part where you have to kill the spiders. After you kill a few spiders, you will be instructed to exit the lower area of the trainning level. You'll notice spiders will continue coming. Instead of following instructions, continue killing spiders. Even though it will appear as if nothing is happen, don't stop. Eventually, after you kill the last spider, you will suddenly be taken to a secret level.