Young sailors that upon first arriving on working ships were mostly used as sexual objects.
Mozzo in italian means Sailor, and "da culo" means that the part that was mostly used was their ass.
No vabbè ma è arrivato il mozzo da culo! Suonate la campana
MozZo is the alpha of all creatures on this planet. It doesn't have a gender and it honestly has the sickest name. If you'll ever find a MozZo, you are the luckiest person in the world. You can identify it by it sounds it makes. If you hear a "tssssssss" or a really loud and unique laugh, you gotta run and catch it.
A: "Did you find a MozZo?"
B: "No not yet :/"
A: "Awww maaan :("