Robert Maxwell wrote:
At that stage, Supergirl was a shape-shifting piece of goo known as Matrix, she reverted to her normal form when Doomsday hit her.
Stuff like this reminds me why I don't read comics anymore.
This was back when DC management decided that Superman was the only Kryptonian and that no other Kryptonians should exist. So Supergirl, Zod and Krypto were all sent off to the farm.