‘Maybe it’s nothing more than what it looks like: a lump of diamond sailing through space, towards Mars. A cannonball. Although the one big modification we witnessed, since Jack and I were almost in the line of fire of that Lethe-spawned weapon inside the Cache, is that it’s somehow got itself wrapped up in Xeelee hull plate – a rough ovoid of the stuff, that somehow assembled itself around the projectile. Maybe it grew in the sunlight from some kind of seed: a Xeelee flower, Jack calls this hypothetical object. Anyhow, it’s a shell that’s added virtually nothing to the mass of the thing but presumably has given it some kind of additional protection. Armour plating, Nicola says.
-Xeelee: Vengeance, Ch. 33