Invincible Warthog

In the level, Outskirts, there is an invincible hog. Continue through the level normally until you get into the long tunnel in which you have to drive a hog. When you go in there, go pass the first "Loading" message. When it is done,turn around and drive all the way back to the crashed Pelican near where you first get the hog. Continue to drive behind the Pelican. You should see the invincible hog on a platform. If you came here before, then the hog will not show up. Jump up there and either use the rocket launcher or drive the hog off the platform. The invincible hog cannot be destroyed, hence its name.