The rules, in this case are pretty clear. The spell never mentions mirrors or reflections, it “summons illusory duplicates." Spell names aren’t indicative of their mechanical effect. See Chill Touch.

There’s also vampire wizard statblock that has Mirror Image on its spell list.

It would be funny if the spell just failed though.

  • themeatbridge
    3•3 months ago

    You’re not wrong about the RAW, but it’s a point of contention for the RAI on how Mirror Image affects non-attacks that target the caster.

    My feeling is that using a mirror on an enemy is like an attack for the purposes of interpreting the RAI on Mirror Image. Mirror Image only specifies what happens if the caster is attacked (the false images have a chance of being targeted instead) but there are Divination spells and some offensive spells like Magic Missile that require no attack roll. Some people interpret that to mean that those spells ignore Mirror Image, but that argument doesn’t track for me.

    Anything that requires targeting an individual by sight should be affected, even if it isn’t technically an “attack” per the rules. It should be up to the DM to decide. The description of Mirror Image makes it clear that it confuses anyone who can see it, making it difficult to determine which image is the real one. It describes specifically how to calculate attacks, but it also doesn’t specifically say that non-attacks are unaffected.

    If you use that interpretation, it would suggest that pointing a mirror is like targeting the character who has cast Mirror Image. You would have to roll a d20 and compare that to 6, 8, or 10 depending on the number of mirror images. Perception can’t see through Mirror Image.

    You might see no reflection (which would confirm they don’t cast a reflection), or you might see the false image’s reflection (which would be ambiguous).

    This all assumes you’re using a steel mirror or similar item to see the reflection. If there is a mirror in the room, you would be able to see more of the room, and presumably you’d be able to tell if the caster had a reflection by comparing the number of reflections you see to the number of duplicates in the room with you.

    • @uid0gid0@lemmy.world
      2•3 months ago

      Mirror image specifies that it blocks attacks that are targeted at the caster. Magic missile has no “attack” component, it automatically hits. Mirror image also ignores AoE damage. The specific wording is “A duplicate can be destroyed only by an attack that hits it. It ignores all other damage and effects.”
      We just had this discussion at our table on Saturday.

      • themeatbridge
        1•3 months ago

        This is one of the issues I have with going from 3.5 to 5e. In trying to simplify the rules, they have left out details that make it ambiguous.

        Here’s the text of the rule from 5:

        Three illusory duplicates of yourself appear in your space. Until the spell ends, the duplicates move with you and mimic your actions, shifting position so it’s impossible to track which image is real. You can use your action to dismiss the illusory duplicates.

        Then there is detail on how it affects attacks

        Each time a creature targets you with an attack during the spell’s duration, roll a d20 to determine whether the attack instead targets one of your duplicates.

        If you have three duplicates, you must roll a 6 or higher to change the attack’s target to a duplicate. With two duplicates, you must roll an 8 or higher. With one duplicate, you must roll an 11 or higher.

        Then there is detail on how the duplicates defend:

        A duplicate’s AC equals 10 + your Dexterity modifier. If an attack hits a duplicate, the duplicate is destroyed. A duplicate can be destroyed only by an attack that hits it. It ignores all other damage and effects. The spell ends when all three duplicates are destroyed.

        Then the rule ends by describing how to bypass the spell.

        A creature is unaffected by this spell if it can’t see, if it relies on senses other than sight, such as blindsight, or if it can perceive illusions as false, as with truesight.

        It does not say that a creature is unaffected by this spell if it is using a spell that does not use an attack roll.

        Magic Missile starts with this:

        You create three glowing darts of magical force. Each dart hits a creature of your choice that you can see within range.

        I would argue that Magic Missile relies on sight, and Mirror Image prevents you from visibly discerning which duplicate is the target. So you can’t “see” which target is the creature and which is the duplicate.

        I know I’m in the minority on this topic, and I’ll always defer to whatever the DM decides. Most people feel that, since it doesn’t explicitly include non-attack targeting, that those actions ignore Mirror Image. But I prefer to play to a common sense interpretation of the spirit of the rules. Like if a teammate tries to toss a healing potion to the Wizard, but it shatters on the ground because they threw it to one of the duplicates. Or casting any divination or enchantment that relies on sight should be affected by Mirror Image, even if there is no attack roll.

        That’s the logic I was extending to include applying a mirror to the target. But that’s probably too far afield from RAW.

    • AhdokOP
      2•3 months ago

      I’m pretty sure that the rules as intended for this one are that it just affects attacks, I’m afraid. Sage Advice repeatedly argues that the intention of wordings like this is that they don’t extend to other effects.

      Of course, it’s perfectly fine to run your table different to sage advice. There’s a lot of stuff in there that I think is rather silly, or bad design.

      Were you able to see the whole space, you should be able to see the illusory duplicates fine (they’re not “vampires” mechanically), but not the real vampire, so I’m in full agreement there.