User blog comment:Omega natsu2/Episode 201: Delivery, Review./@comment-3424593-20141001021226/@comment-4449950-20141001024016

Ah cool, thanks Chaos. Yeah, I just found a translation website that gave me "Hmmm" as a translation rather than "Mumumu", though there's another that quite literally says ムムム means "I'm having exams". No, I am not kidding o__O