Rotten apple for his rotten head a metaphor

Bad apple (or rotten apple) is indeed defined as “someone who creates problems or causes trouble for others; specifically : a member of a group whose behavior reflects poorly on or negatively affects or influences the remainder of the group.” Versions of the proverb can be found as far back as the early 16th century.

Explanation:

rotten  

1       adj   If food, wood, or another substance is rotten, it has decayed and can no longer be used.  

The smell outside this building is overwhelming<endash>like rotten eggs...    

2       adj   If you describe something as rotten, you think it is very unpleasant or of very poor quality.  

INFORMAL   usu ADJ n     (Antonym: great)    I personally think it's a rotten idea...    

3       adj   If you describe someone as rotten, you are insulting them or criticizing them because you think that they are very unpleasant or unkind.  

INFORMAL   usu ADJ n     (disapproval, Antonym: nice)    You rotten swine! How dare you?...    

4       adj   If you feel rotten, you feel bad, either because you are ill or because you are sorry about something.  

INFORMAL   usu v-link ADJ   (=awful)  

I had glandular fever and spent that year feeling rotten...    

Not sure what this question is asking, but I don't believe it would be a metaphor.

the answer is something i don't know

wht excerpt u need to add it