Saber: They're ordinary chestbursters. The mouths look weird because ADI are recycling they're old ones, with the weirdly design mouths, which lack the elastic tendons on either side and look a bit fake. That's why you might get the impression they don't look 'right'. Deco: If you have any sort of hope in actually giving that script to Fox, don't publish it on any public forum! Do that even once and you'll never get them to accept it. Don't even send them the script first. Send them an enquiry letter. Studios never look at scripts unless they've got express legal permission by the author of them, first. If they didn't do that or chose scripts which are in the public domain, they are in danger of being sued by those authors at a later date, if a future project so much as happens to include similar details by coincidence.