Cobrastan is a fake country made up by Jorji Costava, which appears in his fake passport, as his nationality on day 4. According to the passport, Cobrastan has at least one city, Bestburg, which Jorji also made up.
The color scheme of the Cobrastan passport is similar to that of Obristan, which is where Jorji possibly comes from (according to the valid passports he presents on days 11, 19, 22, 24, and 29). The cover of the passport features a cobra.
Cobrastan's passport in the short film adaptation.