Dungeons & Dragons Online

“How I gaslit my friends for months”, aka an “Oblex big bad primer”

Hey gang,

I’ve just finished a story arc that was brewing for about six months with my buds. The focus has been around an Elder Oblex that the party has been unknowingly stalked by for months. I wanted to share my findings on how to run an arc based around an Oblex encounter for a while.

Why run an Oblex Encounter?

An oblex is a formless blob demon that is capable of making copies of anything it digests. After digesting its victim, it gains the memories of its victim, allowing it to use the copies to trap more victims.

It’s great at infiltrating the party or groups because it has all the memories of the victim its pretending to be, AND all the memories of the people it's ever eaten, so insight checks won’t work well on it! It is able to identify all the mannerisms of its victim and replicate them!

Since the copies are also blobs, they can change their shape on the fly. Your copies can disappear under doorways or through pipes. They can change to other victims whenever needed, or even inanimate objects. If your party attacks an imposter, you can just have the imposter get cut down as if it wasn't a fake.

This allows you to create situations like you chase someone around a corner only to find that they’re gone (they escaped through the sewer grate without opening it, or they shapeshifted into a pile of garbage or turned into someone completely different). You can be really creative with it!

The oblex leads well to a horror arc, having your party slowly uncover that people have been body swapped is really fun! It's also a great opportunity to creep out and gaslight your friends!

Why NOT run an Oblex Encounter?

Oblex’s work well when there is a re-occurring NPC that the players are familiar and friendly with that works as the initial victim. Any new person that appears randomly will instantly be suspected when people start going missing or acting weird. If you don’t have an NPC like that, this won’t work very well.

Oblex encounters work best inside urban environments with lots of victims. Having just one victim for an oblex sucks and is really easy to figure out.

Oblex encounters are pretty boring if you just happen to find one in a cave or something. They’re not that interesting to fight, it's everything around them that is fun.

Oblex weaknesses

So there are three main weaknesses with the Oblex:

  • There is a string of blob that attach the copies to the main blob, if it is disconnected, the copy dies.
  • All the copies smell like slightly like sulfur
  • When the cards are out, the oblex is pretty easy to kill.

I do not run the oblex “tethered”. I find this is too much of an obvious weakness that anybody will be able to figure out the moment they meet a copy. It also restricts the Oblex’s freedom heavily.

The smell may also seem like a pretty strong weakness, but remember that Oblex KNOWS that it smells like sulfur. Bruh can smell its own stank.

To get around this, I often just made the copies roll in mud or even simply dump seasoning on themselves. The BEST part about this is that even if your PC’s know that shape changers smell like sulfur, it still weirds them out. “Party: Wait, what does he smell like? Me: Thyme. Party: What the fuck”. Whatever you choose to make the copies smell like can be a recurring theme that creeps the players out.

Homebrew changes

Personally I think that the Oblex isn’t strong enough to be the big bad for an arc for higher level characters.

For homebrewing I actually combined mine with the Juibilex. The Juibilex is the blob demon prince so they fit together pretty well. My party would easily clap even an Elder Oblex, but the Juibilex is a big challenge.

The Juibilex is a pretty boring stat sheet, so spicing it up with a much cooler oblex abilities is pretty fun. It’s strong and smart.

Here is how I fit the two together:

  • The Juibilex gains sulfurous impersonation from the Oblex. The Juibilex is pretty fucking boring without this. Its a blob.
  • Sulfurous Impersonation loses the tethering weakness. It makes it pretty hard to do anything with the imposters
  • The Jubilex gains the Oblex’s weakness to fire. Optional but I added it to give my players a boost in a tough fight.

While you are using the Juiblex statblock for “cards on the table” combat, 90% of your work is going to be done with the oblex abilities. That said, don't forget the jubilex's lair and domain abilities! They really ramp up the creepiness, especially the insanity aspects.

RP’ing the Oblex

This is all optional, but it's a good baseline to get into the mindset of an elder blob imposter.

  • The Oblex wants to be big. It’s ultimate goal is to devour the world and become it. It does not want to “take over the world”, it wants to be the world. Think Tyranids from 40k.
  • The Oblex and its copies share a mind, the copies are the oblex and vice versa.
  • The Oblex started small and like a lich leaves parts of its biomass in safe areas to rebuild itself.
  • The Oblex is infinitely patient and will not kill a golden goose. If the party trusts an imposter and the Oblex has access to tonnes of victims because of the party, it will not try to consume a party member. It’s going to keep that gravy train going for as long as it can.
  • The oblex has access to all the memories of its victims. It will use those memories for intel and ways to garner trust with potential victims!

Playing the Oblex

This is where the fun begins! This is where you get to gaslight your friends!

You’ll need a few things for your Oblex arc:

A Urban Setting

This really only works if your party is in a place with a large population. An Oblex would just kill someone they found in the forest, not try to replace them and gas light them. A big city with a lot of potential victims is easiest, but a small village of 30 people could be pretty intimate.

A city is easiest because the imposters can be city guards, homeless people, pets or things the players have never met and wouldn’t have any reason to be suspicious of.

Victim Zero

This has to be someone the party likes, travels with and trusts. The likes part is optional, but its a great way to inject sad vibes to the party when they realize their buddy has been an imposter the whole time and they died a horrible ooze death.

Getting the party to not be suspicious of Victim zero is HARD. Use a common, reoccurring, non throw away character that is always with the party. If “boblex” shows up one day and people start dying, people are gonna immediately suspect “boblex”.

The character should be useful for the party and should not immediately be the oblex. Since their healer had to step out of the campaign for a bit, I added an atheist cleric npc to the party and he discussed the paradoxical nature of his class with them. They trusted him, and more importantly, it did not look like I created this as a throw away character.

The swap should happen when the party is not looking, and no blobs or shapeshifters are present. Say the marching order has Victim Zero in the back, have them appear late to a fight or something. The swap happened then. If they get left with the luggage, have the swap happen then.

Finally, the victim has to smell bad to mask the sulfur smell, and CANNOT be put into any situation where they need to cast a spell that they could not cast! This is the risk to using a cleric as victim zero because they can no longer heal or anything!

How I did it:

During the events of the last arc, a lot of demons got to the mortal plane, the Oblex was hiding in a shrine full of demon hunters. They went after the shrine of the demon hunter and started pillaging it. The party agreed to clear out the demons. None of these demons were shapeshifters or anything, just vanilla bad guy demons. Shit went down in the shrine and the party had to rush out, cleric included. On their way out, the cleric falls. Tripping is fine, just has to be separated. I DID NOT mention this to the party unless they specifically asked about where he is. The party unknowingly leaves the cleric behind, who gets consumed by an opportunistic oblex and impostered. The party realizes that the cleric is missing (or is reminded) and runs in to rescue him. The oblex makes it look like the victim was horribly burnt, but still alive. This gets around the sulfur issue as a person burnt by demon fire would smell like sulfur. Cleric needs to rest and goes off on his own.

Badda bing badda boom you got an imposter in the room.


This one is most important, this fight should be a long story arc. From victim zero to dead Oblex was about 10 or 15 sessions for us. During that time the party explored candlekeep, fought some kua toa and did a bunch of different things completely unrelated to the oblex. When the party realizes what's happening they should reflect back and lose their shit.

The longer you go before the reveal, the better. The more victims, the better.


“Gaslighting is a colloquialism that is defined as making someone question their reality”

As your oblex is happening travelling, it devours people it gets alone time with. The party meets someone they like, the oblex gets alone time with them, kills them, takes their place. Rinse and repeat.

The more memorable characters you can toss in, the better. They don’t have to be important, just interesting enough to remember.

  • Odd personality quirks are great because you can adjust them after the swap. To use a trick from the “Red Queens War” series, have an NPC say a memorable phrase after every sentence (like “watch me”) then slightly adjust it after the swap then act like nothing changed. Have other imposters back up the claim to gaslight them even further.
  • Appearance changes. Since the oblex is a shapeshifter you can slightly change the appearance of any victim. One of the victims was a scrawny awkward teen before being consumed, after they oblex displayed them as super buff mma fanatic. The awkward Victim Zero cleric slowly started to look heroic and sexy, like Aragorn. This continues the trend of something being very wrong, especially when you have other imposters saying its no big deal.
  • People appearing conveniently when they are needed. The imposter can change its appearance right? It can change into a different victim! Having an imposter guard nearby that switches into story relevant npc’s allowing them to arrive way faster than creeps people out. I did a dungeon where the party took an imposter with them and it took them almost an hour IRL to get to the bottom where they need a different npc. The imposter ran off, switched appearances and came back in under 30 seconds. This created a “holy shit are you usain bolt?” moment in the combat.

Make gaslightling adjustments lightly and subtly. Anything major will trigger alarm bells, but personality quirks changing will not start a crusade by the paladin. If you do drop too big of a hint, thats fine! You can either have a different imposter try and downplay the hint or even just let the reveal happen. At that point the players now realize that they're surrounded by imposters but do not know who is an imposter, thats fun as hell!

As time goes on, figure out a point where you think it's been long enough and start dropping bigger hints. The oblex might get fat with strength, and starts dropping bigger and bigger hints that something isn’t right. This will direct your players' focus to these inconsistencies and eventually to the oblex itself.

Big Plays

Sulfurous Imposter gets exponential fast. An Oblex let loose in a city will grow like wildfire even without your players present.

Imagine the players bring their victim zero to the city. Zero gets their own room at an inn at night, oozes through the floorboards onto the cook working on the first floor. Cook gets consumed, then asks the innkeeper for some help. Innkeeper gets consumed. Innkeeper directs guests to their room, closes the door with guest and innkeeper inside, consumes guest and so on.

Party brings victim zero to a fancy noble party. Victim zero has a quiet private talk with a noble on a balcony, noble gets consumed. Noble orders their servants to attend them, consumes each one of them. Servants consume others and the Noble sets up meetings with other nobles to consume them with an army of consumed servants there as backup.

Guard is on patrol, hears a noise created by Victim Zero in an alley. Heads down the alley, gets consumed. Consumed guard goes on his rounds then consumes the other guards in the barracks. Consume enough guards and one will be a royal guard. Consume enough other royal guards and you’ll get some eventual time with the King. Commit some imposter regicide and the Oblex has access to a kingdom.

It’s ABSURDLY easy for the oblex to pick off people, which allows it to gain access to more victims.

You don’t have to keep track of these murder lines, but keep track of any time that the party just allows Victim Zero to be alone with people, if they have access to a guard, assume that the guard (and eventually after some time, the king) is compromised and so on. The longer it goes, the more victims they will have. Remember that the Oblex is incredibly patient, there's no sense in risking a messy kill that outs them.

The Big Reveal

Eventually the oblex will reach critical mass and will need to expand into more areas. This might show up with parties that are a bit slower or haven’t been paying attention. That's fine! Just start dropping bigger hints!

Things like:

The king has been replaced, he randomly starts ramping up for war with another kingdom for some reason. The oblex wants more biomass, and the biomass business is booming during war.

A noble house tries to start a civil war.

Underground freedom fighters try to rise up against the (imposter) king and recruit the party, but unknowingly reveal their plans to the Oblex (remember, the oblex is a single mind, it does not need to report back to HQ to drop off intel! Anything the party learns while an imposter is present the oblex also learns!). The party shows up the next day only to find that they’re completely cool with the king and are disbanding the rebellion….because they’re all dead and replaced.

Eventually the party will figure it out, and then the Oblex will reveal itself. The party will probably be super upset about this then try to fight it.

From the on, it’s up to you how you want to handle it! The players will prob try and figure out the extent of the infiltration, so be ready for that!

My final confrontation with the Oblex involved a multistage fight where the players would fight in the core memories of the victims that were close to them, with the last one being victim zero. Imposter victim zero had told them that he hated them for abandoning him so they felt extremely guilty. The soul of the original victim zero appeared during the memory to give them a little boost and explain to them that he does not hate them, creating a nice little moment. Having memory fights like that is like a gut punch to them because it reminds them of how they failed those characters.

Hope this helps!


Similar Guides

    None Found

More about Dungeons & Dragons Online

Post: "“How I gaslit my friends for months”, aka an “Oblex big bad primer”" specifically for the game Dungeons & Dragons Online. Other useful information about this game:

Top 20 NEW Medieval Games of 2021

Swords, dragons, knights, castles - if you love any of this stuff, you might like these games throughout 2021.

10 NEW Shooter Games of 2021 With Over The Top Action

We've been keeping our eye on these crazy action oriented first and third person shooter games releasing this year. What's on your personal list? Let us know!

Top 10 NEW Survival Games of 2021

Survival video games are still going strong in 2021. Here's everything to look forward to on PC, PS5, Xbox Series X, Nintendo Switch, and beyond.

You Might Also Like

Leave a Reply

Your email address will not be published. Required fields are marked *