So there is in fact some old remains of religions in the Land of Ooo. Maybe from before the Mushroom War?
Evidence:
Mary and Baby Jesus in Marceline's house
Jake wearing Jewish clothes
Natasha confirmed that it was Baby Jesus by the way, in Marceline's house, and Mr. Muto confirmed Jake was wearing a yarmulke. Oh and didn't the candy people go to the church to worship "Glob", and LSP says "Oh my Glob" quite a lot.
So now I wonder, does Marceline only have that painting because she likes to look at it, or is she actually religious? And is Jake really Jewish or does he just dig the style? :P
Of course, Glob can also be the Cosmic Owl or some other new deity that is important to the Candy People and the other characters.
So, what do you guys think?