Judging from the way he appears, Boldo could well be a ghost whose particular gimmick involves "possessing" food.
Magical Soup Genie, actually. The DVD says so, with the Build-a-Boldo game.
Complete Monster: Boticelli Remorso is the cruel leader of the lower rat world. Believing the only true meaning of life is other people's suffering, he forces innocent mice, such as the protagonist, Despereaux, into incredibly one-sided gladiator-like games in a Colosseum, pitting them against a gigantic (to them) cat where the only outcome is being eaten and dying in front of a crowd of bloodthirsty rats. He despises Princess Pea for no apparent reason, and as such orders his hundreds of rats to eat her, trample her and cause her great pain. A detail throughout the movie that adds to Boticelli's status as a monster is the skulls and bones littered throughout Ratworld; it is made clear this is his and his subordinate's doing. Throughout all of these events, Boticelli is happy with it, because, as mentioned, he loves other people's suffering.
Uncanny Valley: Princess Pea. Her body is the same proportion as the other humans, yet her head is about twice as large with a forehead that could hold a heliport.