66067
I'm reading the _Dragon Ball_ manga and characters keep sort of stammering
"mu-mu-mu" at various moments, for example below. What does this mean?

[![enter image description
here](https://i.stack.imgur.com/JCJsR.png)](https://i.stack.imgur.com/JCJsR.png)
CC BY-SA 4.0
2019-03-17T23:12:33.927
66061
2019-03-18T01:42:39.763
1515
question
interjections
What does "mu" mean as an interjection?
I love this comic too. Mu mu mu expresses frustration in a calm way.
CC BY-SA 4.0
2019-03-18T01:42:39.763
66067
2019-03-18T01:42:39.763
33332
66061
answer