Air swimming

A Grunt air swims. It can be seen in the video around the 01:41 mark. -XDkTflQu5k This glitch is when a Jackal (or anything that's killable, but Jackals get it more often) is killed by a grenade explosion and their body gets stuck between two objects like Covenant boxes.

The glitch happens where the body is too big to fit in between and so the body hovers in the air between the two objects and looks like it's trying to swim.

Note
In Halo 1, when you make dead bodies fly into the air by means of explosives, they look like they're trying to swim.