This easter egg can be seen in a cinematic. On the level Delta Halo, at the very beginning were you see the Grunt (looks like he's playing in the dirt but isn't), look closely at the Grunt and you will notice that he has a Master Chief toy and a Grunt toy in his hands, it's easier to see it if you take a picture and zoom in with a editing program, or have a modded Xbox that lets you detatch the camera then freeze time and look at the grunt. If you have Halo 2 Vista, you can use the detachable cam.