[Tyhm]

It's a really good start...
Suggest the following: Each segment's distance from their shadow is determined by a function of sine(x*y), so they sort of "wave" when they walk instead of being constantly hunched over like that.
Health is shown by the number of segments, kinda like in Centipede. This is one of the ongoing gripes about Bomys, they don't show health at all.
New heads. Don't even bother using the existing. Make a Bomy Template sort of head, then you can have them bite attack more realistically.
Sounds are always good, if you can get them.
Either they have to be a whole lot weaker (human level at least: 3 hearts and 0.5 damage), or rarer (see also: Bomy Hatchlings). Maybe the player, Bomy or Human, has to do a quest in a cave with a door that only opens on Sylvester, then is closed for the rest of the year, so you have 1 Graalian Day to get the Dragon Form and get out. Unsticking means you lose the Dragon form, also that you can't get to the cave again (obviously, it IS Sylvester after all). You have the Dragon Form at full power (which would be insanely powerful) until you die, then it's gone until you can get a new one.