The colossaly tiny whale
A whale of colossal magnitude, with eyes covered its body.
Upon entering The Private Demiplane, the party was shocked to see a colossal whale before them, seemingly very hungry. It attempted to eat them, and then attempted to suck them in with some supernatural power. It appeared as though its mouth was a portal to nothingness, hence perhaps why its mood did not improve once it was fed berries.
The party communicated and found this creature to be very unhappy, and, not knowing if they would ever be able to return here, they turned it into a mouse and took it with them. Graminea Malkovich communicated to it telepathically, where it told her it wished to eat for eternity, and came from “darkness”. However in its mouse form it seemed to be able to eat, and feasted on raisins.
Graminea named it Steve.