she pinned an elite into a wall with a Banshee and fired on them for a solid minute

In the original Halo on Xbox, I found out that if you keep meleeing a dead elite, the blood splatter keeps getting reapplied to the ground around it, and the existing splatter never despawns. Do this for a minute and you can bring the frame rate of the game down to a single-digit-number.

To the game’s credit, it doesn’t crash or stop responding, it just keeps skipping frames to make up for the excessive graphics processor use. And if you turn away from the blood, the frame rate returns to normal. But your “paint job” remains in memory as long as you are on that level. As soon as you look at it again, the frame rate drops again.