A very lovely pattern, and I am very happy to have found it.

But the friend I did this for wanted a magical creature, so I changed the pony into a unicorn.

Changes to the pattern:

• the horn, obviously
• less obviously, I simplified the ears a bit; mostly because I wasn’t able to produce enough ear parts in the same size.
• I slimmed the legs down a bit.

ETA Precise description of changes

Legs

1) MC 6
2) inc ev st = 12
3) inc ev 2nd st = 18
4) inc ev 3rd st = 24
5) inc ev 4th st = 30
6) sc, using inner loop
7) sc
8) 6x (3 sc, dec) 24
change color
9) 4 sc, 4x dec, 4 sc, 2 dec, 4 sc = 18
10) - 25) sc
Forelegs: 26) - 31) sc
Hind legs: 26) inc ev 3rd st = 24
27) - 31) sc

Horn

Version 1:
1) MC 4
2) - 3) sc
4) inc ev. 2nd st = 6
5) - 12) sc
13) inc ev 3rd st = 8
14 - 20) sc
21) inc ev 4th st = 10
22) sc

Version 2 (unfortunately not photographed before I gave that unicorn away. But I actually think it’s more beautiful):
1) 32 ch, turn
2) 30 dc from 3rd st, 2 ch, turn
3) 10 dc, 10 sc, 10 sl st
Using the natural tendency of this to spiral form into cone shape and sew together.

Ears:
Any changes I made should be ignored - the original ears from the pattern are much better.