Horses in Their Car Seats

Was driving Lydia in the car several months ago. (Mary usually drives)
Lydia: You're 'tending (pretending) to be Mama.
Adam: 'Cause I'm sitting in Mama's seat?
Lydia: Yeah, and there are horses pulling the car and baby horses buckled in their car seats, and the mama horses are pulling the car!
(Don't know if we talked about horse power, or if she was just into horses at the time)