I don't think they can quite be classified as the usual type of imaginary friend: for a start, Item doesn't really believe in them. And she doesn't talk to them so much as be them. It's like a benign form of multiple personality disorder, and it has precedent in this household. The Boy is fond of making up characters (mostly cats) and talking in their various voices, so I suppose, on reflection, this is not surprising.
Finally, these characters only 'appear' when I am there, so they do not act as a friend to a lonely only child or anything like that. It's more of a shared fantasy.
It started with Talpa. Talpa is a mole which I apparently acquired from a pet shop. At first he could only say "Lemony" but as he got used to his new home, he became quite talkative and is always very agreeable. When surprised, he has a particular way of saying "Oooooh". It is one of the most sublime and mellifluous sounds I know. If you ask him what he is doing, or wearing, today, it is always exactly the same as what Item has planned, and yet Talpa claims not to know Item.
He is a very pleasant pet to have around; he will pop up whenever you say his name with a cheery "Talpa here!" (or "Moley here!") but disappears for lengths of time, possibly to visit his friend Orangey who lives next door. When we went to The Boy's parents at Christmas time, by coincidence, Talpa went to Orangey's parents' house which is next door to theirs.
There is also Bananabits, Talpa's nemesis, whom we have never met but have heard dire things about. His most notorious crime was weeing in Talpa's drink.
Then there is Curious Mole. Curious Mole is incredibly annoying because mostly he just asks "What's this?" about everything in sight, too fast to actually answer. The only way to make him quiet is to tickle him.
Finally we have Big Mole (usually played by me, on request). Big Mole has a habit of mistaking Talpa for a lovely comfortable rug or cushion, and then feigning surprise when he begins to move or yell.
All of this meant that the first chapter of The Wind in the Willows went down a storm as Item's bedtime story last night. As you'll remember, it begins with Mole having a spring clean. And when the 'cheeky moorhens' made an appearance, she was almost delirious. The moorhen-who-was-really-a-coot from our Amsterdam trip is still fondly remembered.