Philosopher's stone

The Philosopher's Stone is a lifetime reward in The Sims 3: Supernatural. This object allows a Sim to turn portable items into gold ingots. as well as allowing the household to summon playable ghosts. However, there is a chance that the Sim will fail in the attempt to turn the object into gold, or worse, die by turning into gold. Should a Sim be killed by such accident, the gold statue may be sold for an hefty sum, and can be named by the sim killed in the action, should the Sim be revived.

It is quite inefficient, as gold ingots produced by an individual action is around 150 simoleons. This is compounded by the risk involved in the transmutation (although one could exploit it by giving the sim Death Flowers, or give the sim Unlucky or Loser trait), despite the lack of motive cost otherwise (asides the time) in using the said reward to produce the gold ingots.