money-spinner

noun2

1. •
   (UK, figurative) Something that generates a continuous income.

   • One cannot resist the impression that the doctrine that a person who has been harmed in some way is a victim, and therefore cannot commit any wrong, has been turned into a money-spinner by lawyers. — 2011
2. •
   A money spider.

   • She never passed a spider or moneyspinner, without throwing it over her shoulder, to the no small annoyance of those who might be near. — 1859