There are certain points on the Halo 2 Campaign where it is possible to face unlimited supplies of enemies.
Locations
- Delta Halo
- After acquiring the Scorpion tank, fight your way through the level. When you reach the area where Cortana would normally say "They're all pouring out of the middle", stay in the tank, don't get out of it at all. Up on the structure where all the Covenant shields are, you will see an endless supply of Grunts. They appear from 'the middle' about three or four at a time. Once you leave the tank, the supply will end.