an 'ugly duckling' that has become a beautiful swan [=an ugly/unsuccessful person or thing that has become beautiful/successful]
('informal') That dog of yours is '(as) ugly as sin'. [=very ugly]
The house is an 'ugly duckling', but it has a lot of potential.
(..) Mrs. Lao, it is my very great pleasure. No, no, no, no. She does not speak English. Watch this. You ugly horse! She doesn't know. "Ohhh." See? She goes "Ohhh" all the time. Watch. Shaved ape. "Ohhh." (..)2012 The Dictator