The Sims: Unleashed (released September 25, 2002) is the fifth expansion pack for The Sims. It adds many new features, such as farming, going to community lots, and about 125 new objects as well as 5 brand new careers. However, the main new feature is the ability to own pets: cats, dogs, birds, fish, or reptiles.
The Sims: Unleashed is featured in episode 3 of the 4th season of "Six Feet Under."
There is a bug in the game, sometimes referred to as the Upside-down head syndrome or Upside-down face disease (among other names), which causes the Sim icons to change into incorrect images, or for the Sim heads to become invisible. The bug is caused by corrupted character files. The only verified solution is to delete the character file, though if a backup of the character file exists, it can be imported into the game after the corrupted file is deleted.
The Sims Unleashed is the only game in The Sims series to change its intro video.
The zydeco music introduced in The Sims: Unleashed was written and performed by the Zydeco Flames, a real-life zydeco band. They were the first music artists who re-dubbed their original songs into Simlish for the game.