Baby Face

Here's what the director had to say about the design of the aliens in Bird Box (which were ultimately cut from the film)...

“There was a point where we were like, ‘Do we need to [show] it?’” director Susanne Bier told io9. “We got beautiful, beautiful designs and then realized, ‘No. No we’re not going to do it because it’s not really about that.’” 

When we spoke to Bier about the decision not to show the creatures, we also asked what the actors were told about what their characters were seeing. The answers apparently varied. 

“Some of them asked about it,” she said. “Some of them would ask me and I would then suggest certain things, and some of them would just not say anything and just kind of see whatever they had in their mind and be equally terrified and distraught.” Which, she pointed out, is similar to what would have happened in Bird Box’s world. “Each individual would have a different perception than the other individual,” she said. Basically, in the end it was settled that nothing is scarier than your own imagination.

I do think it was a wiser choice not to show the aliens, especially this particular version. It leaves more to the imagination and forces the viewer to create their own idea in their minds.

Plus, giant evil baby-looking aliens might have distracted from the horror and unintentionally turned it into something a bit more campy, which would have been a completely different move altogether.

Here's the trailer...