According to an interview for BBC Radio, having lived beyond his life expectancy twice, first beyond the age of five and then beyond 30, O’Brien identifies as a zombie; this has informed his recent works, including his comical uses of zombie imagery in works such as "If It Were The Apocalypse I’d Eat You To Stay Alive" (2015), as well as prompting him to spend his 30th birthday in an abandoned morgue (during a 24-hour performance in 2017).