From OHRRPGCE-Wiki

You really should ask permission before you use him in anything. Bob the Hamster is a trademark of James Paige and Hamster Republic Productions, and if you do use him in anything you should always include a footnote somewhere saying so.

James doesn't really object to fan-fiction, fan art, and other types of fan-created content, but he still requires you to ask permission because trademark law says if he does not enforce his trademark, he loses it.

[edit] See Also

• Can I make my own version of Wandering Hamster?
• Can I make a game with speaking hamsters? (and if so can I include Bob in it)?