Why does Gus have a shark fin now?

[marisa]

Gus has a shark fin shaped casque (sp) now? This happened in recent weeks!! I have photos to compare and you can really see it:

Before (you can see that area has a lot of shed on it but is still solid)
<img src="http://8snakes.myftp.org/marisa/Reptiles/gus/gus09-03-03.jpg">
<img src="http://8snakes.myftp.org/marisa/Reptiles/gus/2gus08-20-03.jpg">

This is what it looks like now:

<img src="http://8snakes.myftp.org/marisa/Reptiles/gus/gusnovember03.jpg">
<img src="http://8snakes.myftp.org/marisa/Reptiles/gus/2gusnovember03.jpg">

What's going on up there?! He looks crazy! Is it a bad thing health wise?

Marisa