Re-watching Phantasm II the other day, this little critter got my RPG juices going. It's something out of Stuart Gordon's From Beyond with just touch of John Carpenter's The Thing and, now that I think about it, Total Recall.
Backbreakers like to hide in unsuspecting bodies. Your damsels in distress, your old,haggard men begging for copper pieces on the roadside, stuff like that.
Shortly after the adventurers start talking to this NPC from hell, WHAM-O! A slimy caterpillar-snake thing but with a humanoid face erupts from its host's flesh like it was bursting out of an eggshell. Maybe it laughs maniacally or belts out a doom-laden shriek... perhaps it speaks in an eloquent but deep voice of fishcakes and mannequins that move in the dark? Oh, man - what if this creature had a bunch of suckered tentacles? Roll for initiative, chumps!
HD: 5 HP: 37 AC:11  Attack Bonus: +3 #Attacks: 7 Damage: 1d12 (bite), 1d6 x 6 (tentacles dripping with foul ichor)
Special: vulnerable to fire, resistance to poison, acid, and psionics. If a Backbreaker scores a critical hit (natural 20) with a tentacle, instead of double damage, that area becomes swollen and discolored within minutes. An hour later, tiny humanoid-faced "sperm" explode out of the wound doing an additional 3d4 damage (unless healed by a 5th level cleric or higher), as well as, scaring the bejezus out of everyone watching.
Treasure: Usually none; however, there's a 1 in 6 chance that a Backbreaker will mutter some black secret of the nameless void as the thing drools blood and yellow puss from its repugnant visage. Something like, "This is not the end. Another universe awaits - a place of fire and darkness you could scarcely imagine... and fluffy pink rabbits."
Authored by Venger Satanis