One of the Creation War's (1486 DE - 8777 DE) epic engagements was the Battle of Šadullu. This two week long battle was fought on the ground and in the skies over Šadullu.
The Covenant's Supreme Commander Bal-Kriav and the Covenant generals Silvanus and Danzar-Khâl fought the Nine-Tongued Worm while it was trying to destroy a world then known only as Sphere 411.
In this epic fight, the the Nine-Tongued Worm destroyed the Šadullu continent, broken free from its terrestrial roots, it floated upwards to the monstrosity's gaping maw; a one-way rift back to the Sea of Entropy. After having one of its tongues severed, the behemoth fell reeling back to Chaos.