I think this fits the description of them better than the official stats, since they are described as being so long supposedly no one has ever seen the rear end of one.
Khisanth, just out of curiosity, what did you imagine she would look like? I always thought the "Shark of Worlds" part was supposed to be metaphorical, myself.
What about they are reduced to 1 percent of their HP then? Just losing 25 percent (how it official works) seems like it would be nothing more than a nuisance, particularly if it can only affect someone once per day.
OH I thought I'd make a fix for Doombringer as I always thought it seemed way too weak. I also took away the preform 70 ranks and razor tongue prerequisites, as that makes no sense to me.
Doombringer (Cosmic) (SU)
You can cause foes to re-experience old wounds.
Prerequisites: Cha 70
Benefit...
What if I made if I made it higher tier? I guess part of why I made it is it never made sense to me that you got a penalty to attack rolls for being big. If anything, you'd think it would be the other way around, since if the body part they are attacking with is bigger it would be harder to dodge.
Here's one I'm not sure about:
Size Adaptation: Divine (ex):
Prerequisites: Gargantuan size or bigger
Benefit: You no longer take a size penalty to armor class and attack rolls.
Also what would Grendel's mother be like? I'm thinking just use the stats for Grendel but give her like 10 more HD and make her at least Huge size (and increase her strength and constitution appropriately).