Vinatge Barbie Horse Walking or rolling Weird Blue Box

I just found this a few Hours at the Salvation Army.
It looks like a Vintage Barbie Toy horse (so I thought),
but on front left leg it says it is made by Blue Box, made in Hong Kong.
It looks so barbie like, including the mane natura hair.
The eyes are real old school black.
and it gets even stranger, it has wlees below the hooves and a motor inside, BUT I cann find where I put the batteries.

Can anybody help me?
Is this Barbie, or a Barbie look alike? Did Blue box make horses for barbie?
Is this supporsed to be a walking horse? if so, where do the batteries go???

I am dazed and confuzed on this one.