Simple nondescript harmless looking dark rocks which hold a terrible power that when unleashed turns even the most peaceful creatures violent. Noble creatures big and small become vicious and unmanageable when infected with black rock.  What is worse yet is that the infection comes from the mages that encounter these beasts.   It is a simple spell but with dire consequences.

To simply utter the magic incantation will cause a chain reaction within the rock exploding with violence.  After the thick blue smoke subsides the effects begin turning any somewhat sane mage into a raving maniac with the ability to infect those around them.  They have claimed to hear voices telling them to do horrible things, and given the black rock disease to pass to others.

One mage when interviewed was heard to say, "Oh Shut Up! Get out of my head!"

Is there any more to be said to this?  These black rock elementals and the other fiendish minions from the Pit of Hell should never have been summoned to this realm.   Now they are here it is the quiet and innocent that must suffer to do their bidding.  Several of the DAGR's are possessed by this fiendish trickery from the depths, it is yet unknown what ill effects yet remain for these who have been overcome by such an illness.   Perhaps an Exorcism will be required to rid them of their vexation.