Heh, this thing is mythical, so let's go with 20HD.
Poison looks ok to me, unless you want to make it do Con damage or something.
What's the intent of the "grappling attack" in the Spikes line?
Well, it can use them as a normal melee attack, so they can by default use them in a grapple. And the wording is "grapple attack."
.
Actually, this gives me an idea, too. Want to give it Improved Grab and maybe also Swallow Whole?
I'm a tad confused. I suggested using Impale, which is like Constrict in that it automatically deals damage on a successful grapple check when they're already in a grapple, which is what I think you're suggesting. For me, it's just a matter of using the more standard monster ability wording, not the mechanics.
Nah, Constrict is for bludgeoning damage, Impale is for piercing damage.But, yeah, I really prefer to stick to standard abilities.
Are these ready for the fluffy stuff?