Illusions: A Practical Guide

Illusions are tricky, both in that they’re complicated to use and that they’re good for tricking people. Understanding these spells thoroughly can help you as a player or as a DM to accomplish all sorts of things, often handling problems without resorting to violence.

In this article, we’ll examine spells which produce “illusions”: a false sensory effect of some kind which is not specific to a target creature. This is kind of an arbitrary definition, but the intent is to limit this to some closely-related spells with significant overlapping mechanics. Mastering any one of these spells requires understanding all of them, because knowing when to use a spell is just as important as knowing when to use a different one.

Keep in mind that illusions depend heavily on your DM being willing to play along, which in turn requires your DM to not be tired of your shenanigans. This article offers some modestly clever suggestions for applying illusions both in and out of combat, but be aware, if your DM gets tired of your illusionist solving every problem with Minor Illusion, they’re going to start making creatures investigate every illusion you create.

Be respectful. Don’t be a problem. If you’re worried about how your DM will respond, have a polite discussion with them and warn them ahead of time that you’re going to rely heavily on illusions. A little bit of courtesy, respect, and communication goes a long way. If all goes well, you can enjoy a long career of wreaking havoc on the world with your nonsense while you, your DM, and your party all laugh at the absurdity of it all.

If you’re looking for Minor Illusion in Baldur’s Gate 3 please visit Practical Guide to Minor Illusion.

Table of Contents

Comparing the Spells

Before we dig into the specifics of our subjects, let’s examine the differences between each spell at a high level. These spells work very similarly, but each has limitations on which senses it covers and knowing those differences can help you pick the right spell for the situation.

Spell NameMinor IllusionSilent ImageMajor ImageProgrammed Image
Duration1 Minute10 Minutes10 Minutes*Until Dispelled
ComponentsS, MV, S, MV, S, MV, S, M*
Dimensions5-ft. cube15-ft. cube20-ft. cube30-ft. cube
* – See the text of the spell.

The Spells

Minor Illusion

Your starter illusion, and arguably the most impactful. The 5-foot cube maximum size is alarmingly generous, allowing you to easily conceal objects and creatures beneath inconspicuous objects like crates, barrels, boulders, etc.

This is an amazing tool for infiltration, diversion, and other shenanigans. You can create loud noises, which is especially nice for sneaky characters because Minor Illusion does not have a Verbal component. Drop out-of-place objects somewhere to draw people’s attention, then sneak past while they’re investigating the golden bejeweled crown that suddenly appeared in the middle of the room.

Minor Illusion doesn’t require Concentration, which makes it great for use in combat when you’re concentrating on something else. Cast Minor Illusion to produce a small wall to duck behind, and, so long as you move from behind it before attacking, it’s almost as good as full cover.

The text of the spell states “If a creature discerns the illusion for what it is, the illusion becomes faint to the creature.” Since you’re creating the illusion, you can rewasonably discern that your own illusion is, in fact, an illusion, allowing you to see through the illusion while other creatures can’t. Then, from the safety of your illusory garbage can, you can safely cast other spells without giving away the illusion so long as nothing you cast has a visual effect which emanates from you. It’s almost as good as invisibility so long as you don’t need to move.

Against enemies small enough to fit entirely in one 5-foot square (your DM might complain about at medium-sized creatures like humans), you could conjure a box around them. They’ll reasonably try to touch the box on their own turn, allowing them to see through the illusion, but, until then, they can’t see out, which means that they can’t make opportunity attacks.

Silent Image

Silent Image exceeds Minor Image’s visual option in two ways: the 15-foot cube is 3 times larger on each side (we could measure volume, but that’s not helpful in DnD), and you can move the illusion. With a 10-minute duration, you may be able to repeatedly make use of the same casting of Silent Image by relocating it rather than re-casting like you must with Minor Image.

You can make the illusion move in a way that makes sense of an object/creature you’re replicating, so if you pick something suitably large like a giant snail or a carriage with something obscuring the space beneath it, your whole party can hide inside the illusion and move along with it. Your DM might get a little picky about movement and positioning while you’re acting in initiative order, so try to save this gimmick for outside of combat.

In combat, Silent Image can be just as effective as Wall of Stone. If creatures don’t have any reason to suspect an illusion and couldn’t normally smash through a stone wall, they’ll likely try to find a way around an illusory wall rather than trying to force their way through it.

Major Image

A direct upgrade from Silent Image, Major Image adds another 5 feet to each side of the cube and adds the ability to produce sound, smells, and temperature. So long as you don’t expect creatures to interact with the illusion while it’s in motion, Silent Image is typically sufficient.

However, a little bit of thought can improve the benefits beyond just being larger. To repeat our illusory stone wall example, you could instead conjure a wall of red-hot iron, and have it feel hot in the area on either side of the wall. You can’t deal damage, but if you walked up to a wall of red-hot iron that appeared from thin air and the air around it felt hot, would you be dumb enough to touch it?

Want an illusory elephant with believable hot, foul-smelling breath? Here you go. How about a red dragon coiled up and sleeping atop a pile of treasure? That should buy you some time.

However, animating creatures does have some limitations since you can only make the creature’s movement look normal. There’s no mention of things like breathing. If creatures investigate, they’re just as likely to succeed at disproving the illusion as they are with Silent Image. You need to do enough to make them less curious so that they’ll never try to investigate.

Programmed Illusion

For 25gp you can permanently troll people with Programmed Illusion. Most things can’t dispel magic, so, as long as your programmed illusion isn’t on cooldown, it’s basically permanent. The 5-minute duration of the animation, the generous wording on the triggering conditions, and the 10-minute cooldown mean that you can create a 3-part animation which runs continuously, each segment triggering the next.

More realistically, you’re going to use this to lay traps and distractions for other creatures. Create a programmed illusion of yourself being distracted triggered by creatures entering a room. Wait for your enemies to walk up behind you to attack, then ambush them. Leave the Programmed Illusion in place like magical candy wrappers on the side of a road because you can’t be bothered to dispel your own magic.

Countering Illusions

I know it’s fake. You know it’s fake. But you need to actually prove that to yourself before you can see through it. This typically requires either physically interacting with the illusion (things can pass through it) or an Intelligence (Investigation) check. As a DM, I generally don’t require that creatures (players or otherwise) are specifically checking to see if something is an illusion. Simply investigating something and rolling well enough should be enough to notice that something isn’t real.

What exactly constitutes “physical interaction” isn’t as clear as we’d hope, so there’s some DM interpretation to be done here. Obviously if I put my hand through an illusory plate of food, that’s physical interaction. But what if someone else does it? If I see Hungry Bill put his hand through that same plate, does that reveal the illusion for me? Probably. Similarly, if I see a Fire Bolt or an arrow fly out of the side of a box with no openings, that seems like enough physical interaction to reveal an illusion.

As a player, investigate at a safe distance. Throw things like sand or gravel, or poke things with a 10-foot pole. Even if the thing you’re investigating is an illusion, whatever is behind it might still be dangerous. If you’re in combat, a player who can make multiple attacks could use one to throw or fire a weapon at the suspected illusion. If your arrow/javelin/rock passes through the object in question, that should be enough to reveal it as an illusion.

As a DM, consider the intelligence of your creatures. A creature of average humanoid Intelligence (10-ish) likely wouldn’t suspect an illusion that makes sense (illusion of a wine bottle on a table, illusion of a horse in a barn, etc.), but might get curious about things that seem out of place and might decide to investigate if they’re not occupied with something else. Creatures which saw an illusion appear in front of them are especially likely to be curious and investigate. In combat, creatures likely won’t take the time to investigate unless something appears unusual enough that it’s more important than attacking.


Aha! You fell for the illusion! This isn’t the conclusion: It’s a clever illusion placed directly in front of the actual illusion, leaving just enough space to hide this paragraph.


Illusions are a ton of fun, and for a clever, well-informed player they’re a powerful tool. You’re now that clever, well-informed player, so get out there and cause some mischief.