f Itachi can see chakra with his sharingan as it was shown,then he can see Muu when he goes invisible,as it was stated that Muu hides his chakra and presence,but my question is how does he do that without chakra?
If Itachi can see Muu then he proceeds to slay the way he sees fit
[*]If he can't see Muu's perfect camouflage,then I don't see what's stopping Muu from driving a kunai towards Itachi's brain and calling it a day.
Personally I'm leaning towards the second choice as it's more reasonable of the ,but the other isn't completely off.