Dobugero-sama

(from ebookjapan):
In this troubled work by the heretical genius George Akiyama, a boy named Gero Tobu, who is possessed by Dobugero-sama, an incarnation of God, rescues the souls of people. On a stormy day, Dobugero-sama, the savior of souls, appears before the parents looking for their missing son, Gero, in the form of Gero and clad in rags. Dobugero-sama, who preaches using difficult words, is smacked on the back of the head by his father and reverts back to his former self, the bullied boy Gero. ......!?

An work of early Shonen Gangan. Was intially collected as a wideban under Enix, then reprinted with Akiyama's early work Amazon-kun by Seirinkogeisha (the edition currently in print).