I am new to D&D. I have always liked mimics in all sorts of games like Enter the Gungeon or Terraria. Can my character's race be a mimic?
[RPG] play a mimic PC
character-creationdnd-5emimic
Related Solutions
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.
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.
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!
Anyone can attempt to do that
Anyone can attempt to do anything, whether they have the feat to do it or not (even try to recall everything accurately, as in Keen Mind). It doesn't mean they will always succeed, but it also doesn't mean they need the feat to make an attempt.
This is an example of bad wording, for a feat
The way this feat is framed implies that only characters with this feat can succeed. Drawing on the wisdom from the Unearthed Arcana: Feats, specifically on the "bad feat" (as identified in the article) named "Warhammer Master," we learn the following:
The ability to knock aside an opponent's shield is nifty -- but that's something any character should be able to attempt. Locking that down into a feat threatens to limit the game's flexibility. You could argue that anyone could still try that trick, but the way the feat frames the ability makes it sound like only characters with this feat can succeed. This option is an area that I'd want DMs to adjudicate on their own, rather than bloating the game with fiddly rules.
This is in response to this part of the Warhammer Master feat:
In addition, you can use your warhammer to knock away a foe's shield. If you hit a creature that’s using a shield, you can have the attack deal no damage and force the creature to drop its shield.
The design goal, as far as Mike Mearls was concerned, was to write feats in such a way that they did not limit the game's flexibility. The way this part of the Actor feat is written implies you need to have the Actor feat to even attempt to mimic someone's speech.
How do non Actors do it without stepping on the feat?
I believe the non-obvious but valid intent, which will still grant this ability to everyone else without necessarily needing to step on this feat's toes, was to imply that the Actor is so good, they can mimic anyone after one minute's worth of study. Everyone else has to take at least a few hours before they can even try properly.
Listen to a chirping bird for a minute, or a bubbling brook, and try to mimic that sound. You might be able to, but you probably can't; but, someone in the world probably could (out of the 7B people on Earth, chances are pretty high, right?)
This feat makes your character so good, they will find that person is themselves, for any sound or speech pattern.
What do they roll?
The Actor feat gives us the guidance for what skill to use:
A successful Wisdom (Insight) check contested by your Charisma (Deception) check allows a listener to determine that the effect is faked.
This makes sense as you are trying to deceive someone that you are what you are not. Based on this feat, then in most cases, you should roll Deception vs Insight. However, for non-Actors, you could use different skills as you see fit.
A Charisma (Performance) check could replace Deception, if you interpret this particular check as a test of how masterfully they can mimic another sound. Perhaps they are openly mimicking robins singing to an audience of children.
A Charisma (Stealth) check could replace Deception, if they are trying to hide by creating noise that makes them blend into the environment.
If interpreted this way, then for the Actors, the predictability of what skill to use means they know where to put their proficiency and Expertise, should they acquire them. This makes this feat even more useful, because for Actors, they always know which skill to use.
Best Answer
5e has a Changeling PC race in the Wayfinder's Guide to Eberron (p. 60), which gives you the ability to transform into other humanoid forms:
From my experience of mimics, their ability to imitate other objects relies on their ability to stay still, which I don't believe is viable for a PC.
Note: This race is not part of the core rules, so speak to your DM to see if they are willing to let you play this race beforehand.