Carlos Huante's Facehugger Centipede attack

leading from

Carlos Huante
and 
The hammerpede

a) Carlos Huante wanted to introduce the concept of a face hugger centipede as if this was the first thing that the Engineers had created, the precursor to the face hugger, a centipede version of this creature with a perhaps a hundred fingers, this thing crawls around and then in the movie grabs the victim by the arm leading to the impregnation in the film

b) And so it was imagined that elements from the face hugger centipede experiment resulted in the Facehugger. But in the final movie, Ridley would transform the idea into an attack by worms transformed by the black goo into creatures known as Hammerpedes

c) Carlos explored the idea that this human's impregnation by the alien centipede leads to an entity referred to as Belugahead and Babyhead shown in his early storyboard and another version of the transformation displays a humanoid with a male member with testicles growing out of the back of the head that seemed to show up in the head of a Carlos' version of an alien humanoid.

Carlos Huante's Babyhead storyboards

source quotes:

1. Carlos Huante: I go" Oh, we have to have the, the precursor to the facehugger, that looks like this centipede thing that is -- centipede of the facehugger who's got like a hundred fingers.  (40:00) This thing just crawls around and that's the thing that attacks the guy, grabs him, it grabs his arm, then we could have that cool 1970s science-fiction astronaut you know, looking at his arm. This thing has grabbed his hand, and you know, that'd be cool, right? And I know Ridley's all about that. He gets that.(Furious Gods documentary)
2. Carlos Huante: Facehugger centipede - to show that this design worked but was an experiment and elements were used for the 'Facehugger'. (Carlos Huante's Alien Notebook)

Hammerpede from Carlos Huante's Alien Notebook