Probably by trying to squish it's ugly skull. 

The links might be handy in the first IC post, too. Easier to find them threads that way, if the subscription screws up again.About the Adventure:
What I'm contemplating at the moment is a Hollow World game. You'd start out being from the surface, from Mystara (as the original setting had). There'd be a fair amount of exploration/discovery, but with a great deal of room for complex social interactions.
Character Creation:
3.5 rules.
12th lvl (66,000 XP).
Standard Point buy with 30 Points.
Hit Points are HD/2+1 (d4=3, d6=4, d8=5, etc) for 2nd level and up.
Standard starting gold for 12th lvl (88,000 gp), can't spend more than 2/3 on any one item.
No item creation during character creation.
All standard PHB races, and any variants with a lvl adjustment of no more than +1.
Pretty much all classes or prestige classes available.
Good or neutral alignment.
Anything specific you want from the other books, please ask about it and I'll consider it.
IC
OOC1
OOC2
RG