The Thing (1982)

Adventure Plot:

Group of adventurers, either by accident or mission, stumble across mysterious remains. The remains, unbeknownst to the adventurers, begin to "assimilate" first the NPC's. Assimilation will result in death of original NPC, of which the creature will have shapeshifted into that role - awaiting its next victim.

Adventurers will have to identify who among them is real or imitation and isolate the threat.

Adventure Hooks:

d20 system. Low magic if any. Reliance will be on adventurers skills, technology at hand, and wits. Vitality point system will be utilized. Hit Points can't replicate the nature of "dread."


Alien of origin or at minimum supernatural. Very similar to the creature as depicted in the movie The Thing.


Does the d20 system have such a creature? If not, what creature/special ability/template combinations could possibly replicate such a creature?

  • \$\begingroup\$ Please do not answer in comments. \$\endgroup\$ Feb 19, 2015 at 11:12
  • \$\begingroup\$ Ruut, a number of possible options exist in things like the fiend folio and lords of madness. I take it that because they use magic, they're not appropriate answers for this question? \$\endgroup\$ Feb 19, 2015 at 11:13
  • \$\begingroup\$ Well, I would like to attempt to shy away from D&D if possible. Possibly d20 Modern or Call of Cthulhu d20. I haven't checked in Fiend Folio in quite a while, but the atypical aberrations in Lords of Madness isn't quite striking my fancy when I look at the creature in The Thing (1982 remake and 2011 prequel). \$\endgroup\$
    – Ruut
    Feb 19, 2015 at 11:20
  • \$\begingroup\$ @ThomasJacobs Write it up! If the shoe fits I will wear it. \$\endgroup\$
    – Ruut
    Feb 19, 2015 at 11:49
  • 2
    \$\begingroup\$ @Ruut This information you're giving in comments is the sort of thing that should be edited into the question itself, as it's apparently very important. We're here to provide expert answers to your specific problem, not to do brainstorming for "I'll know it when I see it" guessworks. That means including all the specific information you can provide, such as what you already know you don't want, so we don't tread ground you've already covered. \$\endgroup\$
    – BESW
    Feb 19, 2015 at 12:49

1 Answer 1


The Greater Doppelganger, Monsters of Faerûn (p. 35)

Greater doppelgangers are the paranoid’s ultimate nightmare: a monster who can eat your best friend’s brain and then not only look like him, but talk like him, have all of his memories, and wield all of his abilities. It possessed the Alter Self ability to turn into any small or medium sized creature indefinitely and by eating the brain of any medium-size or smaller being (RAW suggests that this is seperate from Alter Self and can be used to turn smaller than Small) and take on its identity alongside its mind, memories, personality and alignment. This suggests being able to cast spells as an arcane caster, but is not mentioned by name. And be careful with plotting against it: it has a continuous Detect Thoughts going on (DC 15). And its social skills are rather good (Disguise +27! Bluff +17!) so your players cannot rely on rolling Sense Motive all the time.

However, it comes with its weaknesses. Casting cleric spells above level 1, a paladin's special abilities or other deity-granted things are not possible because the gods aren't stupid. Also note that Greater Doppelganger cannot hold more than three personalities this way without a DC 16 Will save, and if it acts counter to its alignment it snaps back into its base form for 1d10 rounds. And when it comes down to it the being only has 49 HP on an AC of 17, so for a CR 12 creature it is not very tough.

How to build The Thing

As a core the Greater Doppelganger works, but you might want to make it more, well, alien. I would suggest taking a look at the Warshaper Prestige Class (Complete Warrior, p. 90). Because of its poor wording the feature Morphic Weapons allows you to grow as many appendages as you want without any limit, so if you want to grow tentacles or claws to drag the thing along, you can do that. Or you can give it a bite attack if you want to re-enact that one scene (you know the one) from the movie. Though making this something quicker than a Move Action is advised. Morphic Immunity works as well because it fits the theme of being some alien being with unnatural physiology.

Of course, the end result is a humanoid being. If you want to have something a lot more alien than that take a look at the Phasm, which normally looks like a mass of colored goop. It is a shapeshifter too with more HD, HP, saves and good abilities, though it lacks the more nuanced abilites of the Greater Doppelganger. So if you're content with it you can look at the Greater Doppelganger, but if not you can consider pilfering some of its abilities and slapping it onto the Phasm. And don't forget some kind of way to deal with corpses, because the PCs stumbling upon them will impede the thing's plans.

  • \$\begingroup\$ I like it. I can find a template to make it an aberration. \$\endgroup\$
    – Ruut
    Feb 19, 2015 at 14:09
  • 1
    \$\begingroup\$ It's creature type is a bit ambiguous because it's from a 3e book that was never updated, thought its BAB, HD and saves suggests it's a Humanoid. Then you can take a look at the Corrupted Creature template (BoVD, p. 186), which gives a variety of bonuses but gives negative modifyers to Dex, Wis and Cha and does Vile damage to everything it touches (even with non-attacks, but you can always remove that ability). It also ups its CR by 3, so keep that in mind. \$\endgroup\$ Feb 19, 2015 at 14:36

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