There was more than one Sputnik. Sputnik was a common name for vehicles in the early Russian / Soviet Space programme, Sputnik 1, Sputnik 2 etc They were all invented by the Russians AKA Soviet Union. The team, at least for the first Sputniks, was lead by Sergei Korolev
The unique thing concerning the Sputnik 2 (compared to previous Sputnik 1 satellite) was the fact it carried the first living being into other space - a dog named Laika. "Laika" translates to English as "Barker".