binbougami

From wikipedia:

A binbōgami (貧乏神, lit. "kami of poverty") is a kami or god who inhabits a human being or his house to bring misery and poverty... Several Japanese folklores, essays, and rakugos refer to it.

http://en.wikipedia.org/wiki/Binb%C5%8Dgami

One example of a binbougami is Momiji from Binbougami ga!.