In a manga, while a guy was sleeping, someone used a marker to write on him. He wrote
牛 on his forehead and
空回り人生 on his chest.
Considering it was a joke, can
牛 be offensive or funny in some way?
I think that
空回り人生 could mean something like
loser, but I don't understand why he wrote
牛. It is neither a reference to the personality of the character nor to the plot of the manga.
cow can be an insult in English, but what about Japanese?
You can see the page in question here.