Outside the cave horrors cave there is a slab inside a small grove of dying trees. When you use a black mask on the stone (as there is an indent of one on it) it says that

 

"you feel Something sininster is happening elsewhere...

 

...But otherise nothing interesting happens"

 

 

 

Does anyone know what this is used for?, i've only recently got a cave horrors task and found it (not that others hadn't) is it used in a quest (Rocking out?)

After Rocking Out, you get a dead parrot which you can feed fragments of that rock piece to bring it to unlife.

 

This requires 71 Summoning by the way.

 

 

 

I've never heard of being given that message, though...

heh this sounds creepy =D

 

 

 

im killing cave hororrs atm 2 black masks so far =D

yay, sounds like nice to get that 'rare' pet ! Ty for lightning that one.