Simulacrum and True Seeing

[Bubzors]

My party is heading towards the climatic battles of our campaign and I was going to have them encounter the BBEG as a simulacrum to throw them off and have them waste a bit of resources before the real big fight.

One of the PCs has access to the True Seeing spell and the BBEG has a history of messing with the party with illusions. So the chances are high he may pop it as soon as they encounter him.

My question is, does true seeing see through the Simulacrum? Like do they just see a walking talking snow man? I think it'll be funny and cool if he actually does this, and could save them a lot of resources they may waste if they thought it was truly the BBEG

Simulacrum
You shape an illusory duplicate of one beast or humanoid that is within range for the entire casting time of the spell. The duplicate is a creature, partially real and formed from ice or snow, and it can take actions and otherwise be affected as a normal creature. It appears to be the same as the original, but it has half the creature’s hit point maximum and is formed without any equipment. Otherwise, the illusion uses all the statistics of the creature it duplicates.

[Keravath]

"TRUESIGHT
A creature with truesight can, out to a specific range, see in normal and magical darkness, see invisible creatures and objects, automatically detect visual illusions and succeed on saving throws against them, and perceives the original form of a shapechanger or a creature that is transformed by magic."

I think Truesight would automatically detect the visual illusion on the simulacrum.

However, the simulacrum is not a shapechanger and is arguably not a creature that is transformed by magic. It is a creature created by magic. As a creature, it doesn't have an original form, since it did not start out as a creature.

So RAW, I think true seeing would tell them that the shape of the creature they see is an illusion but I don't think they would see through the illusion to the snow man since the snow man wasn't a creature before the spell was cast.

At least, that is how I would tend to run it. Truesight doesn't actually say that you see through illusions, it just tells you that they are there and that you automatically succeed on any related saving throws. Simulacrum is an illusion, it doesn't have a saving throw and unlike Mirage Arcane does not say that Truesight can see through the illusion. So I'd tend to rule that the player knows it is an illusion but can't see through it which might actually be enough to let them figure out it is a simulacrum if they happen to be a rules lawyer :)

[Sigreid]

I'd let the true seeing see it for what it is. The smat ass in me would replace the simulacrum's marker with Frosty the Snowman, including magic top hat.

[DarknessEternal]

It's important to note that truesight doesn't see through illusions. It only detects them. Then the trueseer still has to use an action interacting with the illusion to get a save which they then automatically pass, assuming it's the Image kind of illusion. If it's Phantasmal Killer, sure they'll save automatically.

Truesight does nothing to Simulacrum except detect that it's an illusion. They see the illusion exactly as what it is an illusion of, they just know it is one. And there's no save against simulacrum.

[Ganryu]

I'd let the true seeing see it for what it is. The smat ass in me would replace the simulacrum's marker with Frosty the Snowman, including magic top hat.

I too am a smartass apparently because that's what I would do too.

[Mith]

I'd let the true seeing see it for what it is. The smat ass in me would replace the simulacrum's marker with Frosty the Snowman, including magic top hat.

So my brain decided to take this for a dark twist:

I started with BECMI, so I think of simulacrum as something that wants to kill the original if they are still alive (most clone spells of that era does that).

So in my head, I picture the Truesight slowly peeling back the illusion until they see a icy figurine with a wild grin and eyes burning red with hate staring back at them.

Even if it is bound to be peaceful, it is still full of wrath.

Now you can make it different, but I like sorcery being inherently dangerous vibes.