History
Timesucks are planet-sized humanoid creatures. If attacked, they can release a black gunk that decimates everything surrounding them. The first Timesuck Marko and co. encountered was at first mistaken for a planetoid, because it was not born yet and still an "egg". Creatures and other inhabitants could have lived on it in egg form. A second Timesuck, this one more grown, was in the path of the moving comet known as Phang.