Are there any other practical reasons for choosing proficiency in Intelligence saving throws, other than seeing through illusions?

Are there any other practical reasons for choosing proficiency in Intelligence saving throws, other than seeing through illusions?

It was suggested to me to take the Resilient feat. I considered taking Intelligence, but I can only think back to a handful of occasions where I used an Intelligence saving throws and it was always to do with illusion magic.

RESILIENT

Choose one ability score. You gain the following benefits:

  • Increase the chosen ability score by 1, to a maximum of 20.

  • You gain proficiency in saving throws using the chosen ability.

(PHB p. 168)

I mean, other than to have a better chance of seeing through an illusion spell, is there any point in having a proficiency with Intelligence saving throws?

It seems like it is the least useful out of all the saving throws proficiencies.

Dexterity, Wisdom and Constitution get used the most; Strength and Charisma less so, but Intelligence…

Of course, if you are in a campaign where illusions are very common, then yes I can see how this could be very beneficial, but for most campaigns I can’t see the point.

Are there any other uses for the Intelligence saving throw, such as to counter a monster’s special ability (other than an illusion)?

This is a question about saving throws, not ability checks.

Are lower level illusion spells capable of producing illusions that animate passively?

Can lower level illusion spells, specifically minor illusion, silent image and major image, create an illusion that can passively animate itself without requiring any further input on your part?

There have been a couple of other Q&As about this but they don’t seem conclusive.

  • Can Minor Illusion create animated illusion to Follow a creature? – I answered this, but wasn’t able to find anything that specifically suggested that minor illusion or silent image can be passively animated, so I assumed they can’t be.
  • Is Silent Image animated if an action is not used to move it? – the top answer suggests that silent image at least needs your action to be able to do, but there are comments arguing the lack of RAW support:

    The phrasing in major image is almost identical. It says nothing about the image moving “passively”. – Szega Jun 22 ’18 at 8:50

I’m guessing the answer will be definitely no for minor illusion, probably no for silent image, but I’m not sure about major image, and in all 3 cases, I wouldn’t know how to prove these assertions from their respective spell descriptions.

Question about what a “Deck of Illusions” can really do

I’m a noob DM and by a random table I gave my players a Deck of Illusion, so questions is about what things can an illusion really do, as the description says.

An illusory creature appears real, of the appropriate size, and behaves as if it were a real creature except that it can do no harm.

Does that mean that any action that does not harm would work? For example, the deck has some powerful casters, can any of them cast charm person in the party? or any other not harmful spell as if it were real?

P.S. Sorry for the crappy English, not my first language.

What counts as “one object” for the Illusion wizard’s Illusory Reality and Malleable Illusions features?

I DM for a player who is considering creating a School of Illusion Wizard. They have correctly noted that many things about illusions in the game are open to interpretation, and have asked me to let me know how I would rule on several interactions, in the interest of managing their own expectations. The following question asks about one of these interactions, with the intent of finding out if there is a definitive answer, and gathering information about what would be a reasonable/practical ruling that others have made at their tables if there isn’t.

The 14th-level School of Illusion wizard feature, Illusory Reality, can make one object in an illusion spell real for one minute (PHB, p. 118):

When you cast an illusion spell of 1st level or higher, you can choose one inanimate, nonmagical object that is part of the illusion and make that object real. You can do this on your turn as a bonus action while the spell is ongoing. The object remains real for 1 minute. For example, you can create an illusion of a bridge over a chasm and then make it real long enough for your allies to cross.

The object can’t deal damage or otherwise directly harm anyone.

Although the intent is that you can only use this feature on one object per illusion spell, this answer suggests you can use it multiple times on the same object while the spell persists.

But what exactly does “one object” mean, in the context of the 6th-level School of Illusion wizard feature, Malleable Illusions (PHB, p.118)?

Starting at 6th level, when you cast an illusion spell that has a duration of 1 minute or longer, you can use your action to change the nature of that illusion (using the spell’s normal parameters for the illusion), provided that you can see the illusion.

With Malleable Illusions, you can change an object in an illusion into another object, into a creature, or into something else (like graffiti on a wall).

This answer suggests that if you did so to an object made real with Illusory Reality, the changed object would remain real.

So: it seems like you might be able to make your “one object” real multiple times, while using Malleable Illusions to change it to a different object each time (if you can’t alter objects made real with Illusory Reality using Malleable Illusions, just wait until they are illusions again before using MI).

Is this actually possible?

(Obviously you would still only ever be able to have one real object per illusion spell at any particular time.)

As an example, consider this sequence of events:

  1. Create an illusory sword (with a spell such as Major Image)
  2. Make the sword real with Illusory Reality
  3. Wait a minute for the sword to become illusory again (whether you can apply Malleable Illusions to an object made real by Illusory Reality, and thus skip this step, is the subject of this question)
  4. Alter the nature of the illusory sword to be an illusory lump of coal instead
  5. Try to apply Illusory Reality to make the coal real. Can this be done?

Are illusions just mind tricks or do they produce physical images and sounds?

Do illusions exist as images and sounds in the world, like holograms, or do they exist only in the beholder’s mind, like mass hallucinations? There are paragraphs in the PHB that can support both assumptions.

Clarification: the question primarily concerns illusions produced by Minor Illusion, Programmed Illusion, Silent Image, Major Image, Disguise Self spells. Spells like Fear or Phantasmal Killer explicitly says they affect creatures, so they are out of the scope.

Illusions as actual images and sounds

Spell description explicitly says that the caster “creates a sound or an image”:

You create a sound or an image of an object within range

When casting an illusion, the caster have to specify a location, not a creature. Anyone who looks at the location perceives the illusion.

Many obviously mind-affecting spells like “friends” or “charm person” are enchantments, not illusions.

While there are creatures immune to charm, there is no creatures immune to illusions. Even a construct can perceive an illusion.

Illusions as mind tricks

The wizard’s arcane tradition describes the School of Illusion as

magic that dazzles the senses, befuddles the mind

Being revealed, an illusion looks different to the perceiving person only:

If a creature discerns the illusion for what it is, the illusion becomes faint to the creature.

When does it matter

There are several cases when the outcome might depend on where the spell effect is located:

Antimagic Field – to be negated, should the illusion “itself” be in the field, or does any creature in the field become immune to illusions?

Detect Magic – assuming that Detect Magic spell can detect illusions, what exactly should be in the 30 feet range to be detected?

Also there are ambiguity with light, vision and line of sight:

Block light – A caster tries to use an illusion to cover a window, or conceal a lit torch.

Block vision – Many cases. A caster tries to hide an object “under” an illusion, but the spell description says it can only “create an image” and not “hide an object”. If we assume an illusion actually can cover an object or a creature, Disguise Self would protect from all LoS-dependent spells, etc.

Do teammates automatically resist (and break) illusions?

I’m a new GM running my first 5e campaign. Among others, the team of runners includes:

  • A Decker with augmented eyes that offer some excellent perception rolls

  • A Face who’s got some middling skill at casting illusions like physical mask, trid phantasm, and improved invisibility

On several occasions now, the Face has cast an illusion spell that was very convincing to the intended target, but which the Decker easily saw through. My (possibly poor!) understanding of the rules tells me that one person resisting the illusion breaks it for everyone. This is decidedly un-fun for the Face, so I’ve been running on a house rule that teammates aren’t required to resist his illusions unless they’re an intended target.

Even if I opt to keep that rule in place, I’d like to understand the official rules’ stance on the subject so I can identify any balance issues I might be introducing.

Is passive Investigation essentially truesight against illusions?

I have been thinking about this for a few days (since taking the Observant feat specifically) and have now seen my logic backed up in this question.

Lets assume a character has 20 passive Investigation. A level 13 caster with 20 INT, has a DC of (8+5+5) = 18.

Does the character see through the illusion automatically?

I am prepared to consider that there is a range requirement on this, which would be answered by the linked question, so this question assumes the character is already within whatever range is required.

Can Ice Knife hit a target under the effect of Mirror Image and destroy its illusions? [duplicate]

This question already has an answer here:

  • Does Mirror Image affect spells that have no attack roll? 6 answers

In this question it was explained that the blast of the knife reaches a 2×2 area.

As the description of the spell Mirror Image makes mention of 4 targets next to each other, could it hit the actual target and make the illusions disappear?

Oozes against Illusions

I recently had players fight a Brown Pudding in my game, then the Thief/Beguiler of the group casted a Illusion spell called Legion of Sentinels (PHB2 p. 116). A headbutting ensued with him about the Ooze’s Mindless and Blind traits.

An ooze possesses the following traits (unless otherwise noted in a creature’s entry).

Mindless: No Intelligence score, and immunity to all mind-affecting effects (charms, compulsions, phantasms, patterns, and morale effects).

Blind (but have the blindsight special quality), with immunity to gaze attacks, visual effects, illusions, and other attack forms that rely on sight. Immunity to poison, sleep effects, paralysis, polymorph, and stunning.

[…]

Does Legion of Sentinels spell works on Oozes?

Can a spiritual weapon interact with illusions of creatures

The description for spiritual weapon states that (emphasis mine)

You create a floating, spectral weapon within range that lasts for the Duration or until you cast this spell again. When you cast the spell, you can make a melee spell Attack against a creature within 5 feet of the weapon. On a hit, the target takes force damage equal to 1d8 + your Spellcasting ability modifier.

As a Bonus Action on Your Turn, you can move the weapon up to 20 feet and repeat the Attack against a creature within 5 feet of it.

If there is an illusion of a creature in the path of where you want to move the weapon what happens?

  1. The weapon cannot pass through the illusion so would have to move around it

  2. The weapon in spectral form passes through the creature whether or not it is an illusion but does not reveal it

  3. The weapon passes through the creature because it is an illusion which then reveals it as an illusion
  4. Something else?