Incentive is related to Profit. Profit is related to Earnings. Earnings is related to Pay. Pay is a synonym of Compensation. 
Moon can be used for Mystery. Moon is a type of Sphere. 
Incentive <--RelatedTo--> Profit <--RelatedTo--> Earnings <--RelatedTo--> Pay <--Synonym--> Compensation 
Mystery <--UsedFor-- Moon --IsA--> Sphere 