Boo is the pet and companion of the Rashemi ranger Minsc, having joined him shortly after he sustained an injury to his head. While there has been scepticism regarding the claim, Minsc insists that he is in fact a Miniature Giant Space Hamster who is intelligent and can converse coherently with him. In the Baldur's Gate series Boo appears as an item in Minsc's inventory but if the player tries to remove him he scurries away and the protagonist receives a harsh glare from Minsc. He also features in Minsc's portrait in both Baldur's Gate I and II but in the second game only his hamster squeaks are heard alongside Minsc's dialogue.
- In Mass Effect 2 and 3, also from BioWare, the player could buy a "Space Hamster" in the human shop on the Citadel. In the Citadel DLC, Shepard tells the hamster to "go for the eyes" if anyone attacks it - something Minsc frequently says to Boo in Baldur's Gate 1-2.