The Peek-A-Boo Baby Ponies were introduced in Year 6 of the My Little Pony line and featured baby ponies with ball-jointed heads. This allowed them to turn their heads from side to side as well as up and down.
The Peek-A-Boo Baby Ponies included Earth ponies and a unicorn. The two boy ponies in the set had Clydesdale hooves similar to the Big Brother ponies, but were not children of those ponies. Some of the ponies also had a tooth like the First Tooth Baby Ponies.