Can an Illusion wizard use Illusory Reality to create a sun?

Question

An idea came to mind while playing a game that involved vampires to create an illusionary sun or something that creates sunlight so that they fight while in sunlight. So if a 14th-level wizard were to create this illusion then make it real using Illusory Reality would it work?

The School of Illusion wizard's Illusory Reality feature (PHB, p. 118) states:

By 14th level, you have learned the secret of weaving shadow magic into your illusions to give them a semi-reality. 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.

So would creating the sunlight work, or would it fail since the vampires would be harmed simply because of their own weaknesses (like a person with a nut allergy if you created a giant nut) and do nothing even though it is real sunlight for the 1 minute?

Answer 1

No (probably)

"Sunlight" is not an object "For the purpose of these rules, an object is a discrete, inanimate item like a window, door, sword, book, table, chair, or stone, not a building or a vehicle that is composed of many other objects."

Assuming that the sun in your fantasy world is like our sun (a ball of fusing Hydrogen about 1.5 million km in diameter at a distance of about 150 million km) then there are no Illusion spells with the area of effect or range to duplicate it. Its also pretty animate and not an object by the rules because if liquid isn't an object then neither is superheated plasma.

If your DM has created a world where the sun is a deity then that would be a creature not an object.

If your DM has done something really cool like this:

And the sun toiled across the sky.

Many people have wondered why. Some people think a giant dung beetle pushes it. As explanations go it lacks a certain technical edge, and has the added drawback that, as certain circumstances may reveal, it is possibly correct.

Terry Pratchett, Pyramids

Then you're going to have to ask her.

Answer 2

You can create illusion of anything,

within the boundaries of the spell you use to create the illusion, mainly

• Where you place the illusion
• How big is the illusion

If you create an illusion of the sun, inanimate, and the mini version of it (major illusion can only create a 20-ft cube illusion), you can make it real using Illusory Reality.

However,

when it becomes real, it is no longer an illusion you can control and must obey the law of physic in your world. You must consult your DM what happens when the mini-sun suddenly becomes real. It might explode, akin to a fireball. It might stay at its form, providing sunlight. It might simply disappear, because it cannot sustain the fusion reaction. Or, it might simply be a bright shining ball, but it cannot be regarded as a sun.

You also ask the ability of the sun to affect vampires. The Illusory Reality explicitly states that it cannot deals damage or directly harm anyone, so the sun, even if the DM agrees it counts emitting sunlight, will not deal damage to vampire or impose disadvantage.