With Prometheus in theatres I was feeling inspired to create a design based on Giger's alien. At the same time I was on a tube train in London and noticed a few women wearing "Baby on board!" badges. So inevitably the two concepts collided and natural conclusion of this ramble is that you can now buy that collision on a t-shirt.
There are two designs:
If you wear these shirts, I would recommend mostly wearing them at night…
Incidentally, If you are pregnant and want a "Baby on board!" badge you can get one by following this link to the Transport for London website.