Even MORE cool D&D monsters (cw gore mention)
HULLATHOIN. This is basically an undead APC, an immense long-fallen beast protected by clouds of carrion flies which rupture from its flesh and disgorging zombie troops from its insides. Goofy yet creeptastic right?
But what really pushes the concept to glory is there isn't a whole and healthy version of the original animal around, eating adventurers. Nobody has any clue where necromancers are getting these giant hairless wolverine looking bodies.