Penguin? resembles a green penguin, but is unsure if it really is one. They are one of the main Sumikko characters. Most of their time is spent searching for the answer as to what they really are.

One autumn day, the Sumikkogurashi go out to camp. They look up at the sky and see a big blue moon shining as bright as ever. According to a legend, “On the night of the big blue full moon that appears once in five years, the wizards will come to town and make one’s wishes come true.” Then surprisingly enough, five sibling wizards fly into Sumikkogurashi’s town! The park, the supermarket, the forest… the wizards put a spell on all these places and turn the town into glittery party venues. Before long, the fun night comes to an end and the wizards return to the moon. But how can it be? Tapioca is among them. Has Tapioca been mistaken for the wizard Five and gone with them? 

(Source: Encore Films)

Sumikko Gurashi debuted in 2012 as slightly negative characters who like to stay in the corner of a room. The characters include "Shirokuma," a polar bear who is sensitive to cold; "Penguin?" (with a question mark in its name), a penguin who is unsure if it is actually a penguin; "Tonkatsu," a piece of pork cutlet that was left uneaten; "Neko," a shy cat; and "Tokage," who hides his nature as one of the last dinosaurs. 

The franchise has inspired toys, books, stationery material, video games--and now a feature film. 

(Source: Anime News Network)

Fourth Sumikko Gurashi movie.
 
Note: The current title is provisional and may change when more info is announced.