Miggy mangs is what you call someone when you want to call them something, but you don't know what to say. it can be substituted for any noun or adjective if you are at a loss for words.
Miggy/Mangs
Hey, who's that miggy mangs.
I don't know, just some mang i guess.
Or
That guy is such a miggy.
What a miggy thing to do!