Okay so everyone's been saying how they look like megabases, but honestly my theory is kind of different.
So for this ship to become a megaship it would have to increase in size, however the cyclops, basilisk and now medusa are all the same size. They also look like evolutions of eachother, but instead of being evolved versions we'll go with the fact GalNet called the Basilisks older than the Cyclops, therefore I propose that the Medusa is the next step, an older Basilisk.
This leads me to a super interesting note, that the "horns"/"claws" that grow on the "petals" of the Medusa, in an older version of the Medusa, would connect up the petals leading to a near perfect octagonal shape, and thanks to the "horns"/"claws" on the center-piece of the ship, it basically looks exactly like an evolved Scout. This would lead me to believe that the Scouts and Interceptors are really closely linked and finally kind of confirm they're all Thargoid design in a design sense.
I think we may get another variant of a fully grown Interceptor soon enough, which has connected petals and an octagonal shape. I'd love that, and then they could bring along the Scout ship in the fight too for the players who want it.