the mani-mani statue has an aura that infects people with a desire for fame and fortune. It seems to be fittingly designed after an Oscar award, but also resembles ancient Egyptian Ptah statues, which are talismans of ritual sacrifice, death and the everlasting afterlife. (See also Sokar statues, spelled similarly to oscar)
The statue has been underneath Porky and Ness's houses for centuries. Its influence is probably the reason Porky's dad is so deranged, abusive, and money hungry.