Free riding on a cool brand. How do you manage to do that? You can copy the cool style of the clothing, you can use a rather similar logo. And, you use exactly the same brand but in a different order.
In this case, it is trademark BILLABONG on one side and BILLON BANG on the other. A somewhat creative copy, if such a thing exists, but the OHIM accepts the opposition and rejects the trademark. Since the consonants are (almost) the same (there is a N more in the attacked mark), the sequence is the same and, moreover, the vowels match, there is a similarity between the signs. Finally, the same length of the trademarks makes that a risk of confusion is present. Sounds like a bang.