Bopi?

What is a Bopi? Stella thinks a Bopi is:
A rubber ducky
A leaf
A book
A blanket
A bottle
A cracker
A stuffed lamb
A shoe
A person on a walk
The camera
The computer
The tub
The couch
The bumble bee
Her rocking chair
Anything on TV
My phone
Trev's phone
Jordan
Sports Den
Balloons
Teddy Bears
Pillows
Music
Her books
Bottles of lotion

WHAT IN THE WORLD IS SHE TALKING ABOUT WHEN SHE SAYS BOPI?