SURPRISE!!!!!!

*ahem*

Surprise, from the original My Little Pony cartoon, is the spiritual ancestor of Friendship is Magic's Pinkie Pie. They do have a similar cutie mark. And in the early sketches Pinkie was a pegasus, before they realized she would be much too overpowered if she could fly. (Can you imagine?)
A lot of the original MLP ponies were a little...one-dimensional. Surprise was usually giggly and yelled "surprise" a fair bit. But She could be dependable on occasion. Surprise and Danny even defeated a foe on their own, though it was the Gizmonks, a one part episode. Still credit where credit is due.