Detect Magic and Supernatural Abilities

[Morof Stonehands]

I’ve looked and there doesn’t seem to be much out there, but does Detect Magic find supernatural things? They say they’re magical, but it’s not explicitly said in the spell description.

Would it detect always on abilities?
Would it ping if there was an ability used while detect was being concentrated on?

What are thoughts, or clear rules about this?

[Duke of Urrel]

I’ve looked and there doesn’t seem to be much out there, but does Detect Magic find supernatural things? They say they’re magical, but it’s not explicitly said in the spell description.

Would it detect always on abilities?
Would it ping if there was an ability used while detect was being concentrated on?

What are thoughts, or clear rules about this?

The Detect Magic spell detects magic auras, which are the detectable and ultimately visible manifestations of only two kinds of magic: "functioning spells" and "magic items." Neither one of these things is supernatural.

The more powerful Arcane Sight spell also detects magic auras, but much more quickly, and this spell explicitly renders magic auras visible to your eyes. (The Detect Magic spell eventually enables you to locate magic auras in your line of sight, which strongly implies that you can see them but does not use this exact word.) Whereas the Detect Magic spell renders magic auras detectable only if they are manifestations of functioning spells or magic items, the Arcane Sight spell, if you concentrate, empowers you to see a magic aura around a creature capable of casting spells, using either spellcasting ability or spell-like ability. These are not functioning spells but only potentially functioning spells (because they haven't been cast yet). However, they are still spells; they are not supernatural abilities.

I don't know of any magic that empowers you to detect supernatural magic as a magic aura.

Even if you could see supernatural magic as a magic aura, what would it look like? A functioning spell or magic item has a detectable school of magic, so we can imagine that the spell's or item's magic aura has a color or pattern that represents this school. A creature that can cast spells has a detectable type of magic – arcane or divine – so we can imagine that the creature's magic aura also has a color or pattern that represents this type. But supernatural magic has no school and no type.

Moreover: a spell always has a spell level, which determines the power of the aura that represents it, while a magic item or a spellcasting creature always has a caster level. But a supernatural ability doesn't necessarily have either a spell level or a caster level. So what power would the magic aura of a supernatural ability have?

I conclude that supernatural magic doesn't manifest itself as a magic aura at all. This makes supernatural magic (and pixies) harder to detect than the "non-supernatural" kind of magic, which I choose to call "preternatural" just so that I have a word for it.

[vasilidor]

It is the cheap workaround that allows the DM to not have his magic beasts and what not get outed by a 0 level spell when they use their abilities to hide.

[ShurikVch]

FWIW, it was addressed in the FAQ:

Can you use detect magic to detect supernatural effects? For example, can it detect a wildshaped druid? - Supernatural abilities are magical, and thus their effects would produce magical auras. Although the detect magic spell doesn’t have a line entry for supernatural effect, you can use the same line as “Magic item (caster level)”—a supernatural effect’s caster level is equal to the creature’s Hit Dice unless noted otherwise (MM 315).

Also, this conversation (https://rpg.stackexchange.com/questions/133050/does-the-detect-magic-spell-detect-active-supernatural-abilities-of-a-creature) on the StackExchange:

But on page 219 of the PHB, it is indicated in the detect magic spell description that ''An aura's power depends on a spell's functioning spell level or an item's caster level" (emphasis mine). Would not that indicates that detect magics detects only spell's or magic item's auras?

@KilrathiSly That's a convenient shorthand the game often uses to avoid having to say spells, spell-like abilities, and supernatural abilities. Spell-like abilities and supernatural abilities are just like spells except in the ways that they're explicitly not, and one of the ways they are like spells is that they're picked up by detect magic.