Item drop on different monster that I will enter

[meruem 0]

Can I request for a script where in I can put/add a certain item to drop by a monster which I can also change the droprate of that item from that monster too. 
 

For example

This week I want zombie to drop gold for 0.01%

then next week I will change it to poring with 0.05%. 
 

Thanks in advance guys.