The United States Patent & Trademark Office (USPTO) has refused to allow Microsoft to renew its Killer Instinct trademark. In a government filing, the office said it would not allow it due to the possibility of confusion with Fox's since-ended television series Killer Instinct.

"In the present case, applicant’s mark is Killer Instinct and registrant's mark is Killer Instinct. Thus, the marks are identical in terms of appearance and sound," a line from the statement reads "In addition, the connotation and commercial impression of the marks do not differ when considered in connection with applicant's and registrant's respective goods and services."

"Thus, upon encountering Killer Instinct for 'video game software' and 'entertainment services, namely, providing online video games' and Killer Instinct for 'entertainment services in the nature of a television series featuring drama,' consumers are likely to be confused and mistakenly believe that the respective goods and services emanate from a common source."

Fox's crime drama Killer Instinct aired in 2005 and spanned just one season.

Microsoft applied to renew its Killer Instinct trademark in September, sparking a belief that the company may have been in some way interested in reviving the '90s fighting franchise.

Though the USPTO has refused to allow Microsoft to renew its Killer Instinct trademark, Microsoft is allowed to respond to the refusal by submitting evidence and arguments to support its claim.