During the development of Zoo Tycoon, Microsoft held an online promotional competition called the "Beast in Show", where fans could vote for a real-life zoo animal to be included in the game. Out of the ten nominees, a polar bear named Magnet won the competition and was included as a downloadable animal. Magnet was born in 1988 and lived most of his life at the Maryland Zoo in Baltimore. He received his name based on the way he stuck to his mother's side and became highly popular with guests, often being seen playing with his favorite red ball.

In-game, Magnet essentially functions just like the regular polar bear, with the primary differences being a slightly different model with a cream-colored coat and having an additional distinct animation where he plays with his red ball. Oddly, despite being a real-life animal, Magnet is still treated as a standard, adoptable animal in-game, which means that it is possible to adopt multiple Magnets that can also be female. Magnet would later pass away on April 28, 2015 at age 26, after suffering from complications from kidney and liver disease.