I have absolutely no idea what Surprise is like. Seriously I was just invited here and I joined because why not. Soooo, this is gonna be awkward.

Surprise is the original concept of Pinkie Pie

4580693 I know who she is, but I just figured she had a different personality and isn't just a recolor.

She's not a full-on canon character, so her personality is really whatever any writer decides it to be....the base line is it's at least a bit similar to Pinkie, that's all.

Well, the way I think of Surprise, just think Pinkie Pie with wings but sane. She's a bubbly pegasus mare who loves to see ponies smile, and tries her best to make it happen without crazy reality bending magic or fourth wall shattering skills. She's always got a shoulder to cry on and plenty of hugs to go around. If you've ever read Harry Potter, Luna Lovegood would be a good character to compare her to. I've also seen people try to make her even more random than Pinkie, but I've always thought that was kind of pointless because Pinkie is already as random as she wants to be. There's no niche for her to fill there, though it is fun to see the interaction between Pinkie and someone just as crazy as she is.

I'd also give her a little more character depth by making her sad herself. The saddest people smile the most after all.

just think Pinkie Pie with wings but sane

Eww, sanity.

The saddest people smile the most after all.