Let me disassemble this construction bit by bit to see if I get it right, ok?
So, の is the explanatory particle. The らしくな part comes from らしい. So らしくない is its negation. Now, I imagine that てきた is the motion 'suffix', right? So it would mean that something is 'coming to seem like' something else. This is actually how google translates it. My question is, why is らしい in the negative? Wouldn't it mean that something 'is not coming to seem like' something else? Plus... the てきた 'suffix' (I'm calling it a suffix for lack of knowledge of a better word, sorry) comes from the て-form + くる. らしい, however, is not a verb, so where does the て-form come from?
Thank you very much.