How can a character investigate whether a lifelike statue is a statue or a petrified creature?
Do permanent spells like Flesh to Stone, or anything causing the Petrified status (in particular a Basilisk's Petrifying Gaze) leave any way for any character to discern whether or not the statue was at some point a living creature?
First, is a petrified creature a creature? The petrified condition says:
- A petrified creature is transformed, along with any nonmagical object it is wearing or carrying, into a solid inanimate substance (usually stone). Its weight increases by a factor of ten, and it ceases aging.
- The creature is incapacitated (see the condition), can't move or speak, and is unaware of its surroundings.
- Attack rolls against the creature have advantage.
You could argue that bullets one and two refer to the creature as it is being transformed, but bullet three clearly refers to its ongoing state. Therefore, a petrified creature is still a creature.
Now all you need to do is cast a long-duration spell on it that only targets creatures (and works on unwilling targets). A 1st-level bard, wizard, or artificer can accomplish this by casting longstrider on the creature/statue, then casting identify on it (to detect longstrider). Longstrider doesn't require concentration, lasts for 1 hour, only works on creatures, and doesn't require a willing target.
If it's a statue, longstrider wouldn't work, so it wouldn't show up on identify. Otherwise, identify will detect the presence of the spell. Longstrider has the added benefit of not damaging the creature/statue, regardless of which it is. If you're concerned about weird DM rulings, you could start by trying this on something you know isn't a creature, like a random piton. (Beware of piton mimics!)
Outside of context, you can't tell the difference between stone statue and a petrified creature by visual inspection.
The spell ends after 1 minute. RAW, there is no "lingering aura" in the case of flesh to stone as you originally asked. In many cases, finding a perfectly lifelike statue should prompt adventurers to ask questions: Why is this in the middle of a forest/underground cavern? Why does it appear to be terrified/running away from something? These aren't necessarily givens though. A medusa who throws fancy dinner parties would create completely different victims than a basilisk in an underdark prison complex. Also, art is just weird sometimes.
RAF, I don't think there is anything wrong with the DM ruling that the party can recognize that there is something magical about the statue, but I recently ran an adventure where statues of political dissidents were all over a city under martial law. The dawning horror of the party as they realized that these were all actually people over the course of several sessions was worth them not initially knowing that fact.
In the situation you described where a party needs to find a petrified prince in a room full of look-alike statues, the "perfectly lifelike" can be used to help the party. If they can discover errors in workmanship, differences in the material (perhaps the official statues are inlaid with metals or only carved from onyx), or have to solve some other logic puzzle, you can turn the guessing game into a memorable part of the rescue instead of a frustrating waste of spellslots.
As richarb points out, players can rely on non-visual characteristics though. A petrified creature is, by definition, a creature with the petrified condition. There are a number of divination spells that can locate creatures/objects, piece together the past, or otherwise provide insight into the situation, depending on your level of familiarity with the relevant cast of characters.
Statues almost always have pupils carved; petrified creatures do not.
A pertified creature might have every individual eyelash and hair stoned. It would take a highly skilled carver to do the same.
A pertrified creature doesn't have chisel marks.
Statues were often painted, so traces of paint in crevices suggests a statue rather than a petrified creature.
Detect magic might not work but there are several other divination spells that could be of use.
Scrying or locate creature would work if a petrified creature counts as a creature.
Augury: 'should I try to depetrify this statue?'
Identify seems a great spell for it, unless your DM is harsh and decides that no spells are "currently affecting it".
I noticed your question mentioned specifically a basilisk's gaze. On page 24 in the monster manual it states:
Travelers sometimes find objects that look like pieces of remarkably lifelike stone carvings of wildlife. Missing parts appear to have been bitten off. Seasoned explorers regard such relics as warnings, knowing that the basilisk that created them is likely to be nearby.
I don't know of any way of using magic, that hasn't been said already, but you could always have your players roll for insight or nature to determine that it was a basilisk.
