Any ideas on what the first half was?
Well, the fourth planet is Mallus. The new arrival was not the first Old One vessel to appear.
The Old Ones appeared to not all be operating in total unity. One of them, perhaps Quetli or Quetzl, was in charge of the ships in orbit.
The one arriving appeared to be bringing a new thing, greeting two Slann of the First Generation who reported on progress with the Dwarfs and Elves respectively.
She (and I'm guessing it was Potec or Tepok,
mother-of-
pearl and all; as well as one whose aspect is the future and deciphering; the feathered
serpent) may have been delivering the seed or prototype of Sotek? Shadow laurel, shadow victory indicating a hidden/unformed/unseen victory over something, the description of the ship from a planet's surface could come across as the twin-tailed comet, the wings formed from the motions of energy the twin tails. But it hadn't yet settled into what it would be/shaped/formed, hence why it shifted between forms, but had a predator's view of frogs like snakes do, and it already had a serpentine form.
And the Old Ones are referred to as "shadowy beings"