The thing inside the ice hadn't had a shape originally, but the more time Alex spent examining it the more familiar it became. When the time came to defrost the block, it was too late, the thing had taken Alex's form. Alex had just stood there, shocked into immobility as the perfect duplicate approached her and slipped one of it's many glassy tongues inside her mouth. Now she could feel something growing inside her, and it felt sooo good. She would soon be just like her doppelganger, ready to spread their corruption to the rest of the world.
Don't worry, this is not a spoiler for Ice Cold Heart, just a different take on what could have been.