What is the worm creature in the cosmos commercial?

It is real alright, not sure if the one shown here is computer-generated or not...

A tardigrade, more commonly known as a waterbear. They are actually 8 legged microscopic animals. They are extremophiles, meaning they can endure extreme environmental conditions and are found in such regions of our planet.

https://en.wikipedia.org/wiki/Tardigrade

The little worm-like creature that was seen in your stool was probably a threadworm (pinworm), although there are other types of worms which can also infect the human gut. The usual symptom of this infection is intense itching around the back passage which is often worst at night and may disturb sleep. The drugs piperazine and mebendazole can both be used to treat threadworms. Piperazine can be bought over the counter at a pharmacy but mebendazole is only available on prescription. If one person in the family is found to have a worm infection it is usually advisable to treat everyone as others may be infected although they may not yet have developed any symptoms. It's also important to wash your hands and scrub your nails before each meal and after going to the toilet to try and prevent the infection being passed from one person to another.

Looks like it's supposed to be a tardigrade, or water-bear. Don't worry. They're almost microscopic. And it does look like CGI to me.

http://en.wikipedia.org/wiki/Tardigrade

it looks like a tardigrade! They are one of the coolest animals, and Neil Degrasse Tyson told me that they are his favorite animal when I met him. They are also known as water bear, and they are able to go into a latent phase where they have been able to survive for decades, and in space without any oxygen!