How about a gigantic ooze made from ghoul heads.
just imagine, a huge moving wave of magically 'liquid' decaying groaning heads. (like a ball pit with air being forced in to increase it's liquid properties)
heheh
Edit: oooh, this could be considered 'recycling' truly dead ghoul parts, so one made purely out of hands could make sense as well, and since the above creature has no 'stomach' it can't ever be even remotely satisfied, thousands of starving ghoul heads sliding like an avalanche towards a party... love it. oh, and if this isn't dangerous enough, give it a banshee wail attack, or some other sound based attack as well.
Edit2: and this got me thinking of bodies of water made out of ghoul heads, and from there.. get this... a 'water elemental' but made from ghoul heads. like the ooze in properties, but more sentient, and capable of rudimentary form of morphing, so it could walk, or slide, or seem as though its just a bunch of floating heads in a large pool of water.
need to make some stats....
BBQ Man