Stasis field glitch
From Halopedia, the Halo wiki
This glitch can only be done on Halo 3.
The Stasis Field Glitch can be done as you play through Cortana and reach the part where you rescue Cortana. There is an interesting glitch. When you're done watching the cutscene, hit the pedestal where Cortana was; it should make the 'sizzle' noise that happens when you hit energy shields, but there is no visible stasis field.