Deep Dive - The Thought Eater

Deep Dive - The Thought Eater

One of the most ridiculed creatures is the psionic platypus, the Thought Eater. While they may seem harmless, you’d be very wrong and very dead. The ridiculous pictures aside, the creature will literally eat your brain, and the last time we checked, you need one to live. So let’s dive into this creature that no longer exists, but we hope makes a glorious return.

1e - Thought Eater

Frequency: Rare
No. Appearing: 1-3
Armor Class: 9
Move: 16”
Hit Dice: 3
% in Lair: 0%
Treasure Type: Nil
No. of Attacks: 0
Damage/Attack: Nil
Special Attacks:
See below
Special Defenses: See below
Magic Resistance: See below
Intelligence: Non-
Alignment: Neutral
Size: S
Psionic Ability: Nil

Monster Manual, 1977 TSR Inc.

The Thought Eater is found in the Monster Manual (1977) for the first time, and we should get the obvious out of the way. The creature's picture is terrible as it is disturbing. No one should be subjected to seeing an emaciated floating platypus with an oversized head floating through the ether. To make matters worst, the Thought Eater has webbed hands and feet it uses to paddle around the Ethereal Plane the same way a real platypus might swim through rivers and lakes. Let's be happy the picture is black and white since the creature is described as sickly gray. The entire image would be hilarious if it weren't so freaky.

A Thought Eater is an unintelligent creature that drains its victims of psionic energy, which is probably where it gets its name from. Unlike many of the creatures we've discussed, the Though Eater isn't malicious in its attacks. The poor thing is just hungry, feeding on the closest psionic or similar energy it can find, which may happen to be your brain. So don't take it personally, which will be much easier when our skinny platypus drains your Intelligence into the single digits and you forget what it was like to have a brain.

You'd think such an 'interesting' looking creature would be easy to spot when it slides up next to you, but here's the catch. The Thought Eater resides solely in the Ethereal Plane, making it near impossible to see. Even if your vision does extend into that plane, you won't be able to attack it until you are in the Ethereal Plane too. It's probably good to figure out a way to do this quickly, as it will become harder and harder to do as your Intelligence slowly drops.

The best way to defend yourself against these creatures is to attack them with your psionic attacks. If you don't have big brain powers, a mind blank spell makes you undesirable to the creature, who will move on to its next victim, which is probably one of your allies. Of course, if it tries to eat the thoughts of your barbarian ally, it’ll pry starve to death.

The Thought Eater exists by feeding on the mental energy of those around it. It begins to eat when it gets within sixty feet of the target in either the Ethereal or Physical planes. The sickly platypus will then absorb any psionic or spell energy the target attempts to use during this time. While psionic characters were relatively rare in this edition, spellcasters were not, becoming a favorite target of these creatures. Every spell level equaled 5 points of psionic energy, and the Thought Eater would continue draining you until it had consumed anywhere from 101-200 points of psionic energy.

Don't think your safe if you're playing a simple fighter. When the Thought Eater gets within ten feet of any creature, it will feed on your thoughts, regardless if you have spells or psionic abilities. When this happens, the Thought Eater is devouring your Intelligence, with one point equaling ten psionic energy points. These points are lost forever. The information does not specify how many points of Intelligence you lose every round, so we suppose if you have a benevolent Game Master, it’ll be only 1 point, whereas if your Game Master has a chip on their shoulder and likes to think they are god, you probably lose about 1d20 points every round.

2e - Thought Eater

Climate/Terrain: Ethereal Plane
Frequency: Rare
Organization: Solitary
Activity Cycle: Any
Diet: Mental Energy
Intelligence: Not ratable
Treasure: Nil
Alignment: Neutral
No. Appearing: 1-3
Armor Class: 9
Movement: 6 (ethereal plane only)
Hit Dice: 3
THAC0: Nil
No. of Attacks: 0
Damage/Attack: Nil
Special Attacks: Psionics, absorb: psionics, spells, and intelligence
Special Defenses: Ethereal existence
Magic Resistance: absorb (See below)
Size: S (3’ long)
Morale: Unsteady (5-7)
XP Value: 1,400

The Complete Psionics Handbook, 1991 TSR Inc.

The Thought Eater first appears in The Complete Psionics Handbook (1991) and is later reprinted in the Monstrous Manual (1993). Not sure how they made the Thought Eater uglier, but TSR somehow managed to do it as the Thought Eater looks like a fossil one might see at a dinosaur exhibit. It still has a head more prominent than it should be on a body of its size and its hands remained webbed but not its feet. At least in the Psionics Handbook, the creature looks ferocious, emerging from the clouds in the Ethereal Plane, intent on eating your thoughts. On the flip side, Monstrous Manual art makes it look like the Thought Eater is posing for a portrait. We're not sure what they had against this creature, but they took out their dislike for it in the art.

Unlike before, this incarnation has one primary goal; to avoid death. It seems this would be the main objective for most living creatures, but we guess the authors needed to make it crystal clear. Since the Thought Eater dies instantly on the Material Plane, you'll probably never see one there for its sake, or if you do, you’ll just assume it’s the body of a platypus that died from starvation. Instead, you'll need to travel to the Ethereal Plane, but even then, we strongly advise you to avoid getting too close or if you can’t help yourself, push your big brain wizard in front of you. What makes them unique is they don't have to go beyond the Ethereal to eat your mind energy, which doesn't seem fair since you can't see them, even if they are right next to you.

To stay alive, the Thought Eater needs to eat brains, specifically brain waves. It's ironic, as the creature itself is unintelligent and its intelligence can’t even be rated. You'd think they might gain a little knowledge from draining your brain, but we guess eating your thoughts doesn't allow that. The Thought Eater still has no physical attack, but it doesn't need them. You'll most likely be on the Material Plane, and the Thought Eater will follow next to you on the Ethereal Plane, softly caressing your brain energy. How the Thought Eater converts psionic and magical energy remains the same, but now the brain sucker can also drain the magical energy from prepared spells, not just when the spell is cast. Poor spellcasters. They can't fall back on the party's fighters to save their fragile existence from these creatures.

Monstrous Manual, 1993 TSR Inc.

We also now have information on how quickly they can feed on you, which is 10 psionic points per round. This means if you have psionic abilities, it will drain 10 points per round, if you have spells, the conversion is 5 points per each spell level, so a 2nd-level spell every round, and if you just have book smarts, it’ll be one point per round. While you think they might be a bottomless pit of hunger for psionic energy, they will eventually let you go once they have reached their fill, though that full feeling is 1d100 + 100 points. So a Thought Eater might have a small stomach at 101 points or a massive bottomless pit with 200 points. Since they don’t attack, you might wonder what they do with this vast quantity of points. They use these points as their food and burn through 3 points per hour, so now don’t you feel bad for not letting the platypus eat all your intelligence? You are starving it!

If you refuse to feed the Thought Eater, and its psionic points reduce to 0, it dies and its body drops into the Material Plane. We can only imagine that barbarians are constantly seeing these dead platypus everywhere they set up camp, confused about where they come from.

The Thought Eater does show up in A Guide to the Ethereal Plane (1998) with just a bit more information about them. They occupy the Border Ethereal, not venturing into the Deep Ethereal where they can’t feed on the intelligence of creatures on neighboring planes. Most creatures on the Ethereal Plane have no problem dealing with these creatures since Thought Eaters have no meaningful attacks and can easily be killed by anyone with half a brain. In addition, the Ethereal Plane literally gives them an ethereal body that keeps them alive, the moment they travel to any other plane, they will die. So it’s not just the Material Plane that’s toxic, but every other plane as well.

3e/3.5e - Thought Eater

Small Aberration (Psionic)
Hit Dice: 3d8 (13 hp)
Initiative: +8
Speed: 40 ft. (8 squares)
Armor Class: 17 (+1 size, +4 Dex, +2 natural), touch 15, flat-footed 13
Base Attack/Grapple: +2/–1
Attack: +4 melee touch (eat thoughts)
Full Attack: +4 melee touch (eat thoughts)
Space/Reach: 5 ft./5 ft.
Special Attacks: Eat thoughts, psi-like abilities
Special Qualities: Darkvision 60 ft., ethereal jaunt
Saves: Fort +1, Ref +5, Will +4
Abilities: Str 12, Dex 18, Con 11, Int 7, Wis 12, Cha 14
Skills: Hide +10, Listen +5, Spot +5
Feats: Alertness, Improved Initiative
Environment: Ethereal Plane
Organization: Solitary or group (1–3)
Challenge Rating: 2
Treasure: None
Alignment: Usually neutral
Advancement: 4-6 HD (small)
Level Adjustment: -

Expanded Psionics Handbook, 2004 WotC

Finally, this little platypus now looks terrifying in the Expanded Psionics Handbook (2004). The Thought Eater stands on all fours, is silver gray, and has a large, curved beak that takes up much of its face. It is now described as having a feline skull with the beak of a bird and claws like a cruel bird of prey. There are spines that run down its back, and it looks like a skeletal being with ethereal proto-matter dripping off of it.

No longer trapped on the Ethereal Plane, a Thought Eater will stalk its prey on the Ethereal Plane before shifting to the Material Plane in hopes of surprising its foe. It can only remain there for ten rounds, but that's ten rounds longer than before. It attacks the target, but if it gets in dire straits, it has no problem just shifting back to the Ethereal Plane where it can lick its wounds and find someone a bit easier whose Intelligence they feast upon.

The Thought Eater's primary attack is still eating your mental energy, now through an ability called Absorb. It's a melee touch attack and, when successful, drains 6 power points from the target if they happen to have psionic abilities. Non-psionic creatures or a psionic creature drained of all power points suffer 1 point of Intelligence damage, providing the Thought Eater with food equal to 6 power points. It must eat 12 power points a day but will treat weaker creatures like a buffet, eating until they have to loosen their belts.

A Thought Eater also has actual psionic abilities in this edition. Detect psionics is the equivalent of the natural trait the Thought Eater had in previous editions. Distract does precisely what you think it does, forcing their foe to focus their attention on something other than the Thought Eater. Precognition lets them get the jump on you by seeing into the future, while psionic daze confounds its victim, who then have no actions while under its effects. Finallythe thought shield protects the creature from counter psionic attacks, which is probably handy when you try to fight back while it eats your brain power.

Expanded Psionics Handbook, 2004 WotC

If you think that a Thought Eater is about as bad as it gets, we are also introduced to the Thought Slayer, the much bigger cousin of the Thought Eater. This creature is a much larger Thought Eater with streams of ethereal mist coming off of its skeletal body and what appears to be internal organs somehow hanging within its frame. 

The Slayer survives by eating brain energy like its smaller brethren and has a few additional psionic abilities in its arsenal. What makes them extremely dangerous is their gaze trait. One direct look at the creature, and you're dead. Do not pass Go, do not collect two hundred dollars, just dead. Your entire brain is sucked dry at that moment, and we hope you don't feel anything as your brain shrivels into a prune. The DC to resist this effect is DC 19 and, for those wondering at home, a 13th-level character is going to have a base Will save of +4, like barbarians and rogues, or a +8 like wizards and clerics. If you only look at the Thought Slayer indirectly, you'll only be dazed for fourteen rounds if you fail the save. Those rounds will feel like an eternity, but it's way better than being dead.

In addition, if merely looking at you isn’t enough to suck away your mind, it also has powerful psionic abilities that allow it to find psionic-powered individuals, break apart your mind, and more. Also, now it can use its mouth to bite you for a painful hit, so you are no longer safe, even if you happen to be a bit braindead. If you do see this creature, well it’s probably too late, but we do recommend running and hoping someone a bit dumber than you was nearby.


This is where the Thought Eater ends, existing no more after the 3rd edition. If we ever see them again is anyone’s guess, but we advise keeping someone with powerful psionic abilities just in case they return to the Ethereal Plane and you weren’t made aware of it.

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Header Art: Monster Manual (1977) by TSR Inc. / Wizards of the Coast

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