What Detect Magic Can’t Detect: Unveiling the Limits of Magical Perception
The detect magic spell is a staple for adventurers and those interested in the arcane. It allows you to sense the presence of magic, but it’s not a magical all-seeing eye. There are significant limitations to what this seemingly ubiquitous divination spell can perceive. Here’s a direct answer:
Detect magic cannot detect several key things: spellcasters themselves (even if concentrating), items or creatures created by instantaneous spells or magic, the spell itself, things within an extradimensional space (like a Bag of Holding), supernatural creatures unless under the direct influence of an ongoing spell effect, creatures and objects hidden by the nondetection spell, and psionic auras or effects. It also cannot penetrate certain physical barriers like thick stone, metals, or wood/dirt.
Let’s delve into the details of these limitations and provide some clarity to common questions surrounding detect magic.
Limitations of Detect Magic
Detect magic offers a powerful sense of magical presence, but its limitations are critical to understand. The spell is defined by its radius and the fact that it detects active magic.
No Detection of the Source of Magic
One of the biggest misconceptions about detect magic is that it can identify spellcasters. The spell text focuses on sensing magic effects, not the inherent magical nature of individuals. A wizard concentrating on a spell is detected because of the active spell, not their status as a spellcaster. When that spell is over, they are just a person to detect magic.
Instantaneous Magic is Invisible
Magic that occurs and disappears in a flash, also known as instantaneous magic, leaves no lasting magical trail detectable by detect magic. This means that items or creatures created by instantaneous spells, like an undead summoned using animate dead, don’t show up on the spell’s radar. The magic was present for an instant and has gone. Only magic that actively persists can be detected.
The Spell Itself is Immune
Interestingly, detect magic cannot detect its own effect. This is a rule to prevent a perpetual loop where one casting could detect itself. This keeps the spell functioning in a logical manner.
Barriers Block Magical Detection
Physical materials can effectively block detect magic. One foot of stone, one inch of common metal, a thin sheet of lead, or three feet of wood or dirt are sufficient to stop the spell from penetrating. This means that magical auras behind these barriers are hidden from the spell’s detection radius. This is a simple but key thing to keep in mind, particularly in dungeons and other closed environments.
Extradimensional Spaces are Off-Limits
Detect magic is limited to a 30-foot radius on the same plane of existence. Extradimensional spaces, such as those within a bag of holding, a handy haversack, or a portable hole, are outside of this range. The contents of these spaces are entirely undetectable with detect magic, offering some secrecy and safety for the items they hold.
Nondetection Hides its Targets
The nondetection spell actively prevents detection from divination spells like detect magic. Thus, any creature or object under the effects of nondetection will not register to someone using detect magic, making it a reliable method for staying off the grid.
Psionics are Not Magic
While psionics are a powerful force that can emulate many magical effects, they don’t register as magic. In settings where both psionics and magic exist, detect magic can only see magic, not psionic effects. A psionic manifestation will appear invisible to this spell.
Frequently Asked Questions (FAQs) about Detect Magic
Let’s explore some additional common questions about what detect magic cannot detect.
1. Can detect magic see shapeshifters?
Generally, yes. A creature actively shapeshifted through magic, such as a polymorphed individual or a dragon in human form, will emit a magical aura if the shapeshift effect is a result of an ongoing magic. However, if the change is through a permanent ability that isn’t magic, it will not.
2. Does detect magic detect illusions?
Yes, it can, in a way. Detect magic will show an aura of the magic school used to create the illusion (typically Illusion magic). The spell does not automatically reveal the illusion’s true nature, just that it is magical in nature.
3. Can detect magic see charms or conditions?
Detect magic can reveal that a creature is under a magical effect (like being charmed or blinded by a spell) because it registers the active magic causing the condition. This provides information about the type of magic involved (such as necromancy), and can be important for figuring out how to counter the charm. It doesn’t give the exact spell that is being used, however, just the general effect.
4. Does detect magic reveal supernatural abilities?
Supernatural abilities and spell-like abilities that emulate spells are picked up by detect magic as if they were spells, with the same limitations. They are not inherently magical, only when they are actively being used.
5. Can detect magic spot a scrying sensor?
Yes, it can detect an active scrying sensor because it is a magical effect. The user will perceive the scrying sensor as a magical aura.
6. Does an antimagic field block detect magic?
Ironically, detect magic will detect an antimagic field as a strong abjuration effect. However, detect magic cannot perceive any magic within the area affected by the antimagic field. The field has a magical nature despite its anti-magic properties.
7. Can elves use detect magic inherently?
Some elves have spell-like abilities that include detect magic, allowing them to cast it once per day at their current level. Elves can use it like any other spellcaster.
8. Can detect magic see invisible things?
No. While detect magic reveals a magical aura, it does not grant the ability to see invisible beings or objects. Invisible magical effects will still be detected, but they won’t become visible with this spell.
9. Does detect magic work on familiars?
No, detect magic cannot detect familiars. Although some familiars are magical creatures, they are not an ongoing spell effect. They are permanent companions.
10. Can detect magic detect a rope trick?
Yes and no. Detect magic will detect the active magic of the extradimensional entrance of a rope trick, but it will not detect the interior because this area is considered an extradimensional space, therefore it is beyond the spell’s range.
11. Does detect magic see undead creatures?
No, it cannot detect undead such as skeletons, zombies, or vampires, as there is no active magic to detect in their current state. The original magic that brought them back is gone. The effect is instantaneous.
12. Can detect magic detect a person that has a magic item?
Yes, if a person is carrying or wearing a magic item, detect magic will pick up the magical aura of the item, not the person. When focusing on the aura of the creature, the user of detect magic will notice that they possess a magic item, as listed in the Detect Magic spell description.
13. Can detect magic detect poison?
No. Detect magic will not detect poison, as that is a chemical effect, not a magical one. Poison will only be detectable by a spell or effect that specifically detects toxins.
14. Does detect magic see an invisible script?
Yes. Any magical script, such as illusory script, will glow visibly to the user of detect magic. It will reveal its magic school.
15. Can you make an Arcana check instead of using detect magic?
An Arcana check is a knowledge-based skill check. It helps with remembering lore about magic, it cannot be used to detect magic that you don’t already have knowledge of. The two are not interchangeable.
Conclusion
Detect magic is an incredibly useful spell, but understanding its limitations is crucial for any adventurer or spellcaster. Knowing what it can’t detect – such as spellcasters themselves, the magic of instantaneous effects, or things hidden within extradimensional spaces – can prevent mistakes and strategic missteps. Use detect magic wisely, but don’t rely on it to give you all the answers. It’s a tool of divination that can only detect what is actively, currently magical.