Okay, I am trying to find the title of this movie and it is driving me crazy. I don't think it is the Unico movie, but I don't really know. I remember that it is a little unicorn baby who is on a quest of some sort and when the baby unicorn gets angry he/she starts running really fast and turns into a large unicorn that I believe is black... but again I could be wrong. I know my descriptions are annoyingly vague but I only remember a few snippets of this movie but I LOVED it as a kid! If you can piece together my insane ramblings please let me know!

Which Unico movie?
There were two aired on cable
In the early 80's

Unico In the Island of Magic

Unico and his friend Ceri are on a quest to
The ends of the Earth, but Cheri tells him
To stay behind. Once he realizes she'd rather
Bear the hardship alone than see Unico suffer
He temporarily becomes a powerful adult unicorn
With wings and flys her there himself

view scene

I know the cartoon... I think it was anime... it was a little unicorn that would run really fast and turn into a big white pegasus. It also had a boy and girl in it from what I remember. I'm so sorry that I don't know the title... I've been looking for this cartoon myself... it is very hard to find... no... I don't think it's Unico either. I read some where that it might be a Japanese cartoon that was just translated into english. I wish I could help out more.