Serious Sam: Siberian Mayhem is a 2022 first-person shooter game developed by Timelock Studio and Croteam, and published by Devolver Digital. A standalone expansion to Serious Sam 4, the game was released on 25 January 2022 for Windows, and on 6 October 2022 for PlayStation 5 and Xbox Series X/S.

Croteam is a Croatian video game developer based in Zagreb. The company was established by Davor Hunski, Damir Perović, Roman Ribarić and Dean Sekulić, four former classmates, in late August 1992. Croteam is best known for Serious Sam, a series of first-person shooters introduced with Serious Sam: The First Encounter in 2001. The company also developed the 2014 puzzle game The Talos Principle and its 2023 sequel The Talos Principle 2. Croteam employed approximately 40 people in 2020 and was acquired by its long-time publishing partner Devolver Digital in October that year.