Can a Mimic mimic another creature?

Question

A mimic is a fun monster, and essential in any good Dungeon.

As you look around the room, your eyes immediately fall on a large, ornate chest, sitting on a small plinth, a faint beam of sunlight illuminating the details in the carvings, the flecks of dust floating about serenely. You walk up to it, running your fingers over the intricate carvings, then just as you lean down to open the lid... it blinks at you. Roll Dexterity to jump out of the way as the Mimic lashes out at you!

Always fun.

However, any experienced player knows that a chest is, more often than not, not a chest. So, DMs learned to get sneakier; turning doors, wheelbarrows, or other simple items into Mimics (or, more accurately, Mimics into other simple objects).

However, what if a Mimic was pretending to be another creature? Say a level 5 party were exploring a dungeon, when suddenly... A Beholder attacks! Now that would certainly make any player evacuate (and in more ways than one). Obviously though, being a Mimic, it'd be a cakewalk for a party like that.

The mimic's Shapechanger trait does state that it can transform in to any object, and only while motionless.

The mimic can use its action to polymorph into an object or back into its true, amorphous form. [...] While the mimic remains motionless, it is indistinguishable from an ordinary object.

So, can a Mimic achieve this, or is there another monster that serves this purpose?

Answer 1

No,

Mimics can only strictly turn into objects, that means things like, doors, door frames, key holes, keys, key rings, door knobs, knockers, peep holes- and those are just the door-and-other-doory-objects Mimics.

But...

Since a dead creature is considered an object, they can turn into a dead creature, if you want. It should be noted that they don't get the creature's stats and attacks.

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Creatures that shapeshift

There are many creatures that can assume the form of humanoids and beasts without casting spells: Metallic Dragons and Deva, come to mind. I won't list them here but you can look through the Monster Manual to find the ones with the "Shape Change" trait.

A creature that can cast Shapechange is also a good candidate for what you want, it is, however, a 9th-level spell.

However, it appears what you want to be able to do is to make the mimicking creature appear stronger than it actually is. Most creatures with Shape Change can only look weaker, one exception could be the Doppelganger- taking the form of, say, an Assassin.

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For Beholders, specifically...

There is a fungus called Gas Spores found in page 137 of the Monster Manual. They can serve the purpose of mimicking Beholders, as they are described as:

A gas spore is a spherical, balloon-like fungus that resembles a beholder from a distance, though its true nature becomes increasingly obvious as one approaches it.

Have fun freaking out your party!

Answer 2

You've already quoted the relevant rules and answered this in your question.

The mimic can use its action to polymorph into an object or back into its true, amorphous form.

It doesn't say the mimic can polymorph into a creature, so it can't polymorph into a creature. This doesn't mean you couldn't homebrew a mimic that could Shapechange into a creature, but that's then up to you.

As for other monsters, well, there's plenty of monsters in the Monster Manual and other books that can change their shape and look like other creatures. It depends on what specifically you're looking for.

Answer 3

As you quoted from the MM in your question...a Mimic can only turn into objects. It cannot turn into a creature, otherwise its statistics would not say 'an object.'

In terms of another creature that can do this...not as a natural ability, no.

Every other shapechanger in the MM is listed as being able to turn into "A humanoid" or one of a short list of options (such as a 'Large Snake' for a Yuan-Ti Abomination). There are no creatures with blanket 'I can turn into anything at all' natural features.

The only way for a creature to turn into a Beholder or any other random monster is either via Illusions, or by casting True Polymorph. Nothing at all like your idea for something like a Mimic that can take the physical shape of something else just because it wants to.

Answer 4

No. However, the mimic could change into a dead body. This is a looser interpretation but could work once. After that, you party will never approach a body without ridiculous precautions.

In the center of the room, next to a chest is the unmoving body of a dwarf...

Dead bodies are an oddity in most rule sets in that they are not living but can be again. By having the mimic turn into a body, it becomes an ordinary object. I said before that this was a looser interpretation and I fully expect other GMs to go another way on this.

I always believed that the best use for a mimic is one that will surprise players and make them think twice about doing something fairly mundane next time around. There is something disturbing about being attacked by sarcophagi, plinths, doors, bookcases, etc.

For creatures/things that shapeshift into others, polymorphing creatures, such as dopplegangers, rakhshasa, some genies, some dragons, etc, are more appropriate.

Answer 5

I would like to put forth another type of answer. You are the DM and can in all honesty make whatever kind of change you would like to the rules. I wouldn't make the decision lightly, but if it adds to the overall enjoyment of your game then I don't know what harm it could actually cause.

There are potential hazards to this though that you should be careful of. If your players are sticklers for the rules, they could feel like you are cheating (but going back to what I mentioned before this would not be adding to the enjoyment of your game). Additionally, any time you change the rules can have unintended consequences you should be prepared to deal with fairly to your players.

I think a better way to get about the situation you want is to take glance at the DMG chapter on creating a monster and simply create a variant of mimic (or just a construct) that can Shapechange into other creatures instead of objects.

Answer 6

A mimic is not able to turn into a monster of any kind.

But nothing stops it from turning into a statue of a monster. You could easily let appear as a statue the so closely resembles a beholder that your party would be unable the tell them appart at first glance.

The whole Idea of a mimic is that it is a living trap. A creature that sits and waits for unsuspecting prey to come past. To walk around and act as another creature would strongly go against its ecology.

Answer 7

As others have already pointed out, the mimic cannot change into humans. I want to add a bit of extra information to that explaining the intention. The extra information in the monster manual makes it more clear. (It's unclear if this is inteded to be rules or flavor)

Imitative Predators. Mimics can alter their outward texture to resemble wood, stone, and other basic materials, and they have evolved to assume the appearance of objects that other creatures are likely to come into contact with. A mimic in its altered form is nearly unrecognizable until potential prey blunders into its reach, whereupon the monster sprouts pseudopods and attacks.

So a human body with all its intricate forms and things like hair is most likely not included in basic materials. The same probably goes for corpses. Also one could argue that very intricate chests with a sigil or similar might also not be as well duplicated as a simple wood table.

Answer 8

No, a mimic can only pretend to be an object. However, (and many other people are saying this as well) it can pretend to be a dead being, could even be human. But it will not be able to move like them or walk and talk like them.

Get a copy of Prey if you can. The entire game's based on mimics!

Answer 9

Basically the answer is no. In the early versions of Mimics description it is quoted that those monsters can only shapeshift into stone or wooden forms. There was also a special species named « Steel Mimic » who can imitate ... Steel. Since then, the original Mimic have expanded his range of mimicry in MM, but the goal is still to have « monster furniture based on raw materials ».

For an animal or creature (or dead bodies), personally, I have used a handmade version of doppelgängers, hunting people by changing into horrible animal shapes (kind of « Stone Age Doppelgängers »).

Answer 10

Not using its innate Shapechange trait. But you could have the mimic wield a wand of shapechange, although you would need to make it so the mimic is extra intelligent so it is able to use a wand loaded with a 9th-level spell. It would only be able to shapechange into another creature with a CR equal or lower than its level, which I assume would be 2 using the mimic's CR.