Researching Upcastings for Spells (And Silent Image for Blindsight)

[Segev]

How big of a power boost to spells is it to do this. Obviously, there's a wide variation based on what, precisely, the upcasts do, but let's assume for the sake of argument that it's possible to make upcasts that are no more or less powerful than upcasts for existing upcastable spells.

Would it make sense to research each upcast independently? To treat it as just researching a brand new spell that happened to have the original spell's base effect and then also these upcasts? Would it need to be higher level at its base just to have the privilege of upcasting it?

This comes up because I am contemplating an upcast to silent image that makes it effective against blindsight and tremorsense. The idea being that major image should already fool those, since every sense is impacted by it - thus, tremorsense would get the appropriate tactile sensations, echolocation-based blindsight would "hear" the appropriate echoes, infravision-based blindsight would "see" the correct thermals, etc. However, I feel that an upcast of silent image to level 2 that fools sight, and creates an "image" of other sensory impressions without being able to actually make those senses be fooled outside of creating the image, would be appropriate. Your silent image of an ogre upcast to a 2nd level spell slot still isn't making any speech or roaring noises, but the bat will still get an echolocation image of it being there. (Or am I being silly because it's an "image" and thus would fool them, even without the upcast?)

But this is something that comes up for other spells, too. I've posited adding upcasts to phantom steed to reintroduce its functionality from 3rd edition. I'm sure there are other spells that have limitations that upcasting might justify removing, too.

Should research into this be allowed? Obviously, upcastable spells are more poewrful than the exact same spell with no ability to upcast them. "Why don't you just make a higher-level spell?" is answered by the fact that an upcastable spell takes fewer spells known/prepared than a new, higher level spell would if you want the base effect and ability to cast from a lower-level spell slot, too. By the same token, an upcast is always supposed to be weaker than what you'd get if you made a fresh new spell at the upcast level. So, major image should be more powerful than a hypothetical 3rd-level upcast of silent image. Not that I can think of what a 3rd level upcast of silent image should or would be.

So what standard would you apply to trying to research an upcast for an existing spell, vs. trying to simply research a new spell?

[Silly Name]

As a DM, I'd be against researching an upcast version of any spell that already has a "this spell but better" version - Silente Image and Major Image,Find Steed and Find Greater Steed, that sort of stuff. The mechanical reason for those spells existing is that they actually modify how the spell works a bit instead of only increasing numerical values. An upcast Silent Image in particular feels like it would suddenly have too many moving parts and weird cases, and just using an higher level illusion is less of an headache, I think.

For something like Phantom Steed, however, where the upcast version would add new abilites to the steed without fundamentally altering the functionality of the spell, I'd certainly allow it.

However, I'd also consider research in how to upcast spells that normally can't be upcast to be pretty much equivalent to researching a new spell, since you would basically apply it to spells that would obtain new abilities and rider effects and functionality, instead of just upping some numerical values like most upcastable spells. And each new upcast would pretty much be its own unique thing, instead of some general magical theory breakthrough that could be applied to all spells.

[solidork]

I wouldn't be opposed to researching the ability to upcast spells that wouldn't normally be able to, but for Silent Image specifically I figure it would just make the illusion's max size bigger.

Getting closer to working like Major Image seems like a strange choice - theres already a spell that does that.

[Psyren]

^ +1 to "just learn the better illusion spell" and "at best, the upcast version would increase numerical aspects like size or duration without adding new effects that make it equivalent or on par with the other spell."

[Segev]

^ +1 to "just learn the better illusion spell" and "at best, the upcast version would increase numerical aspects like size or duration without adding new effects that make it equivalent or on par with the other spell."

For the silent image thing, the specific interest I have is in a level 2 version. I'm not sure a THIRD illusion spell between silent image and major image would be warranted for "now fools blindsight and tremorsense." I do kinda wonder if I'm overthinking it and "an image" covers "an image as seen by blindsight and tremorsense" too. But probably not.

Why do you say "just learn the better spell?" What's the dividing line between "an appropriate upcast" and "it should be a new and separate spell?"

[Pyrophilios]

What you really need is a variation on Nystul's Magic Aura.
Just like that spell can fool Detect Magic, you need a meta spell, that fools other kinds of perception abilities.

It would help out other illusion spells as well and make illusionists more viable for higher play.

[Psyren]

Why do you say "just learn the better spell?" What's the dividing line between "an appropriate upcast" and "it should be a new and separate spell?"

The main line probably would be "does the better spell already exist?" If they want Major Image to be a free option inside the Silent Image spell, they can do that after all. Needing to learn both if you want access to both effects at both levels is a meaningful limitation on the relevant caster(s).

[Segev]

The main line probably would be "does the better spell already exist?" If they want Major Image to be a free option inside the Silent Image spell, they can do that after all. Needing to learn both if you want access to both effects at both levels is a meaningful limitation on the relevant caster(s).

I'm not trying to make major image a free upcast option for silent image, though. :smallconfused:

[Psyren]

I'm not trying to make major image a free upcast option for silent image, though. :smallconfused:

Maybe not the whole thing, but "fooling blindsense and tremorsense" was likely gated behind the former for a reason.

(Assuming it even was. Major Image has some tactile sensations associated, but I'm unclear if those are sufficient to confuse a creature that perceives through vibrations in the earth. I would definitely be okay with a MI fooling some forms of blindsense though.)

[Segev]

Maybe not the whole thing, but "fooling blindsense and tremorsense" was likely gated behind the former for a reason.

(Assuming it even was. Major Image has some tactile sensations associated, but I'm unclear if those are sufficient to confuse a creature that perceives through vibrations in the earth. I would definitely be okay with a MI fooling some forms of blindsense though.)

Yeah, I am not positive that silent image doesn't fool tremorsense and blindsense on the grounds that "an image" would still exist, or that major image is sufficient to fool them, either. I can see the argument for it, but I can see potential arguments against it, too. Either is going to be open to DM interpretation.

PErsonally, I probably wouldn't let silent image fool those senses, but probably would let major image do so. I just think there's room for a level 2 spell that would fool the blindsight and tremorsense senses, but not provide talking or tactile sensations. Essentially, blindsight will "see" that illusory elf just as well as normal sight does, but the elf still can't sing because the spell doesn't provide full audio illusion. Just enough of whatever is required to create an "image" for the blindsight.

[Chronos]

One issue with blindsense is that, in most cases, the rules don't actually specify how it works. If one has an illusion that includes sound but not temperature, does that fool blindsense? Based on our out-of-game knowledge of how bats and snakes work, it probably should fool a bat but not a snake... but the rules don't make any distinction between a bat's blindsight and a snake's, and we're left with no idea at all what it takes to fool a dragon's blindsight. Heck, it's not even clear whether a Major Image would work, because while it does include sound, temperature, and smell, we don't know if some D&D monsters might have yet other senses that we don't even have any conception of. Maybe an undead creature's blindsight works by directly sensing souls, or something.

In this sense, because blindsight itself is treated in a purely gamist way, it would make sense to have purely gameist spell that just says "This spell fools blindsight", no matter how the blindsight works. Now, whether that spell should be its own standalone spell, or an upcast option for another spell, is debatable. I would lean on the side of "separate spell".

As for Phantom Steed, I would say that a player shouldn't be able to research an upcastable version of that, for the simple reason that they shouldn't need to: it should already be houseruled to upcast that way. As it is, it's singularly unimpressive, both in power level and in, well, impressiveness: A wizard riding a shadowy horse is a lot more fun if, when the wizard is sufficiently powerful, the horse runs on water or flies.