Immobile Banshee

The Immobile Banshee glitch is only available in Halo PC.

Walkthrough
First, grab a Banshee and place it near a Scorpion. Get out of the Banshee and ride the tank. Using the Scorpion, push the Banshee so that one of its Gravity Pods is wedged into a crevice on a wall. The tip of the Banshee's wing should be stuck to the cliff wall, preventing it from taking off. The Banshee should now be almost completely immobile and shouldn't move, even if you try to flip it or throw grenades at it.

Another way to make an immobile Banshee is to fly it over a wall, then dropping it so that it's opening will "bite" the wall.

Also, in the multiplayer level Blood Gulch, you can fly the Banshee and land it in a tree that is present at both bases. If done correctly, it will get stuck in the tree and explosions won't be able to dislodge it. It should shake the whole time and not respawn. The inability to respawn is because the Banshee is always in motion, therefore never at rest. Playing with the immobile Banshee can be dangerous. When trying to flip it while you are near the wall, you may be killed.

This glitch requires a little luck and a lot of patience, but it is possible.

Explanation
The Immobile Banshee glitch is one of many glitches that exploit holes in the physics engine's collision-scanning methods.