MoT was given his anthro form by scientists doing an experiment with nanobots. They intended to turn him into a non-morphic horse and succeeded in turning his left hand into a hoof. At that point MoT managed to escape. Ever since Lurker has been trying to find a way to restore MoT's left hand. The nanobots, however, tend to be finicky about being reprogrammed and have been known to change MoT in strange ways. Here we see him after another attempt by Lurker, hand restored but... well... things could have gone better.

For  MoT
Lurker is  randusrattus's character

P.S. There is a Winged Sea Unicorn (or Almaricorn) in heraldry.