Last week, we considered how casters aim illusion spells and began a discussion about disbelieving illusions. This week we'll consider a few more aspects of disbelief -- including the crucial step of interacting with an illusion.
Interacting With Illusions
According to page 173 in the Player's Handbook, you don't receive a saving throw against an illusion effect with a disbelief saving throw until you study the illusion carefully or interact with it in some way. The text uses an illusory floor as an example. The character in the example provided there gets a saving throw by stopping to examine the floor (study) or by probing the floor (interaction).
For game purposes, we can define "studying" an illusion as taking an action (which DMs can choose to make a move action since this is an extrapolation of the rules and not an actual rule) to observe an illusion effect and note its details. Some DMs I know require a Spot or Search check to disbelieve an illusion. That's going too far. Merely pausing and using an action to make the check is enough to allow a saving throw.
Also for game purposes, we can define "interacting" with an illusion as doing something that could affect the illusion or allowing the illusion to have an affect on you. You have a valid claim to an interaction with an illusion when you attack it, touch it, talk to it, poke it with a stick, target it with a spell, or do something else that one might do with a real creature or object.
The key to disbelieving an illusion is investing some time and effort in the illusion. If you decide to ignore the illusion, you don't get a saving throw to disbelieve it. Let's consider the illusory guard from a previous example. The guard is a figment created with a major imagespell, and the caster has left the illusory guard to prowl around a chamber. A character entering or looking into the chamber might react to the illusory guard in several ways, some of which will allow a saving throw to disbelieve and some that will not. Here are just a few possibilities:
Although both hiding and moving silently are resolved with opposed skill checks, the character really isn't doing anything that could affect the illusion and isn't really interacting with it. It would be best to call for the appropriate checks from the sneaking character and then pretend to make the opposed rolls (the illusory guard cannot see or hear the character). The character doesn't get a saving throw against the illusion.
Attacking an illusion is a definite interaction. The character makes the attack, using at least a standard action to do so. Hit or miss, the character makes a Will save to disbelieve the illusion immediately after making the attack roll.
If the attack hits, the character probably should disbelieve automatically (see Automatic Interactions or Automatic Disbelief, below) as the character sees and feels the weapon passing through the figment with no effect (just like swinging the weapon through empty air). If the illusion in question were a shadow instead of a figment, a successful attack would not result in automatic disbelief (there's something solid to hit there).
The DM can choose to make this at least a move action for the character -- as noted earlier, this is an extrapolation of the rules, not an actual rule. No check is required, and the character makes a saving throw to disbelieve the illusion as part of the action used to observe the guard.
This kind of scrutiny merits a standard action. The character makes a Spot or Search check to look over the guard's gear (or possibly an appropriate Knowledge check). A successful check reveals something about the guard's gear. For example, if the illusion's caster included insignia or if a particular uniform style is included in the figment, the check reveals those. In any case, the character makes a saving throw to disbelieve the illusion as part of the action used to study the guard, even if the check fails to uncover any details.
This one might qualify as an interaction, or it might not. Speaking usually is a free action, but meaningful communication between two creatures takes up some time.
If the character and the guard are alone and there hasn't been an initiative roll, the character needs to stick around to note the guard's reaction to the taunt or wait for the guard's reply to truly interact with the illusion. (That's the equivalent of a move or standard action.) The character makes a saving throw to disbelieve the illusion as part of the action used to communicate with the guard.
If this interaction occurs during an encounter, the character could speak as a free action, but she probably would have to wait until the following round to attempt a saving throw to disbelieve. (A real creature would need the same interval to respond, probably using a free action itself.)
According to the Player's Handbook, if you're faced with proof that an illusion isn't real, you disbelieve the illusion without making a saving throw. The rules give a few examples of "proof" that an illusion isn't real. If you step on an illusory floor and fall through, you know that floor isn't real. Likewise, if you poke around an illusory floor and your hand (or the implement you're using as a probe) goes through the floor, you know the floor isn't real.
It's worth noting that in both examples the illusion fails to function as a real object would. A real floor is solid. It supports your weight (unless it breaks under you), and you can't push objects or parts of your body through it. A character could create an illusion that reacts appropriately when disturbed (with a programmed image spell, for example). In such cases, a character interacting with the illusion still must make a saving throw to disbelieve the illusion. For example, if you use a programmed image spell to create an illusory floor that collapses when someone touches it or walks in it, that's consistent with the way at least some real floors work and a saving throw is required to disbelieve even when someone falls through it.
The rules don't say so, but if you create an illusion that allows a saving throw for disbelief, you automatically disbelieve it (you know it isn't real because you created it).
As noted in Part Two, you must take some action that could affect an illusion before you can attempt to make a saving throw to disbelieve it. Some illusion spells, however, allow saves to disbelieve even when you don't use an action to interact with them. The ventriloquism spell, for example, allows a saving throw to disbelieve whenever you hear the figment sound the spell produces. It always pays to read an illusion spell's description for such exceptions to the general rule.
Dealing with the Unbelievable: The rules governing illusions assume that the spellcaster is at least trying to create something believable. When an illusion spell allows a saving throw for disbelief and the caster creates something unbelievably weird, it's best to allow an immediate saving throw. You're the best judge of what's unbelievable in your campaign. In a world where dogs breathe fire (hell hounds), immense dragons fly through the air, and wizards can shoot bolts of lightning from their fingertips, what's unbelievable covers a tiny slice indeed. Still, if the illusion caster is just being silly (singing carnivorous vegetables, bloodsucking bunnies, dancing hippos), it's best to just roll a saving throw.
Pointing Out Illusions
According to page 174 in the Player's Handbook, a character who successfully disbelieves an illusion and communicates that information to others grants those other characters a +4 bonus on saving throws to disbelieve the illusion. The rules don't specifically say so, but a character claiming the bonus still must use an action to study or interact with the illusion before attempting a saving throw.
We're out of time once again. Next week, we'll consider a few miscellaneous topics related to illusion spells.
About the Author
Skip Williams keeps busy with freelance projects for several different game companies and was the Sage of Dragon Magazine for many years. Skip is a co-designer of the D&D 3rd Edition game and the chief architect of the Monster Manual. When not devising swift and cruel deaths for player characters, Skip putters in his kitchen or garden (rabbits and deer are not Skip's friends) or works on repairing and improving the century-old farmhouse that he shares with his wife, Penny, and a growing menagerie of pets.
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