Amulet of False Casting

Wondrous Item, Rare

Popular among con artists and shady merchants, these ornately beautiful amulets are designed to make their users appear magically gifted, without any actual skill. 

The amulet has 9 charges, regaining 1d4-1 charges at dawn. The attuned creature can produce a false version of an evocation spell that they have seen before. Making such an illusion requires no material components, but is otherwise functionally identical to the range, casting requirements and duration of the actual spell. Creating an illusion in this way uses charges equal to the spells level (cantrips are considered level one as they pertain to this rule.) These illusions are identical in appearance and sound to the actual spell, accompanied by sensory effects such as temperature and smell. These illusions can't make sufficient heat or cold to cause damage, a sound loud enough to deal thunder damage or deafen a creature, and so on. A creature can tell that these illusions are fake with a successful DC 18 Intelligence (Investigation) check. They automatically succeed if they know the replicated spell. Contact with any of the effects reveals them to be false.

 Neat. Has shadow evocation energy.

Quote from I_MAKE_UNBALANCED_HOMEBREW >>

Amulet of False Casting

Wondrous Item, Minor Rare

Popular among con artists and shady merchants, these ornately beautiful amulets are designed to make their users appear magically gifted, without any actual skill. 

The amulet has 9 charges, and regains all charges at dawn. While holding this amulet as if it was a spell casting focus, a creature can produce an illusion that mimics any evocation spell that they have seen before. This illusion uses the same range, casting requirements, and duration of the spell it is mimicking but requires no material components other than this amulet. Creating the illusion uses charges equal to the spell's level (1 charge for a cantrip). 

The illusion is identical in appearance and sound to the actual spell, accompanied by sensory effects such as temperature and smell, but deals no damage, heals no hit points and cannot impose any conditions on the targets. A creature can tell that these illusions are fake with a successful DC 18 Intelligence (Investigation) check, or if they know the replicated spell. Physical contact with any of the effects reveals them to be false.

My question is - why not just have an amulet that lets the character cast Minor Illusion at will, and Major Image a few times per day? You get the same effect without having to be so oddly specific about use cases. 

Minor Illusion is a static image, so it can't recreated dynamic spell effects, plus it is only a 5ft cube of space which is no where close to a spell effect. Major image is likewise the wrong size & shape for most spell effects - a 30ft cube, not a 20ft sphere or 100 ft line -

The proposed item is more akin to the Deck of Illusions, but spell effects rather than creatures.

This one seems... odd

So if someone knows the spell being mimicked, they automatically see through it. But if none of the viewers know the spell, why would you need to mimic it exactly? Just make an illusion of a big blast of fire with major image and talk people into believing it was a fireball. No one's going to call you out on the area of effect being wrong

For that matter, even the idea of a DC saving throw to determine it's an illusion seems off, if you're copying a school of spells that generally have instantaneous effects. The saving throw to "see through" an illusion assumes it's ongoing -- an illusory person walking, an illusory wall blocking a corridor, etc. If the illusion is just a single boom, there's no opportunity to examine it. (Unless you're talking about the aftereffects of the boom, in which case a DC 18 seems way too high to determine that the "fireball" didn't actually set anything on fire.)

Also, mechanically... what does the amulet actually do for you? So you create an illusion of a fireball. Does that give you advantage on Intimidation checks against anyone who saw it? If it's just to make flashy booms, there's already a wand of pyrotechnics

The idea of an item that helps someone pretend to be a spellcaster is a cool one, but it feels like there might be a better way to approach it

This feels like something that's designed to waste an enemy spellcaster's Counterspell... that's the only case I can think of where making it appear as though you are casting a specific spell instead of just using Major Image to fake a spell has any value. Overall it feels harmless... I sometimes like to give my players these kind of gimmicky magic items that do something that isn't obviously useful, but can be used for shenanigans, but I'd imagine it's the kind of thing that would have real impact maybe once or twice during the course of a campaign.

Quote from AntonSirius >>

if you're copying a school of spells that generally have instantaneous effects.

 The most well known ones do, but there are many others with persistent effects. Mimicking spells like:

Wall of Fire/Sand/Water/Wind
Resilient Sphere
Sickening Radiance
Maelstrom
Fire Shield

Might have use in some situations.

Quote from AntonSirius >>

This one seems... odd

So if someone knows the spell being mimicked, they automatically see through it. But if none of the viewers know the spell, why would you need to mimic it exactly? Just make an illusion of a big blast of fire with major image and talk people into believing it was a fireball. No one's going to call you out on the area of effect being wrong

For that matter, even the idea of a DC saving throw to determine it's an illusion seems off, if you're copying a school of spells that generally have instantaneous effects. The saving throw to "see through" an illusion assumes it's ongoing -- an illusory person walking, an illusory wall blocking a corridor, etc. If the illusion is just a single boom, there's no opportunity to examine it. (Unless you're talking about the aftereffects of the boom, in which case a DC 18 seems way too high to determine that the "fireball" didn't actually set anything on fire.)

Also, mechanically... what does the amulet actually do for you? So you create an illusion of a fireball. Does that give you advantage on Intimidation checks against anyone who saw it? If it's just to make flashy booms, there's already a wand of pyrotechnics

The idea of an item that helps someone pretend to be a spellcaster is a cool one, but it feels like there might be a better way to approach it

Quote from AntonSirius >>

This one seems... odd

So if someone knows the spell being mimicked, they automatically see through it. But if none of the viewers know the spell, why would you need to mimic it exactly? Just make an illusion of a big blast of fire with major image and talk people into believing it was a fireball. No one's going to call you out on the area of effect being wrong

For that matter, even the idea of a DC saving throw to determine it's an illusion seems off, if you're copying a school of spells that generally have instantaneous effects. The saving throw to "see through" an illusion assumes it's ongoing -- an illusory person walking, an illusory wall blocking a corridor, etc. If the illusion is just a single boom, there's no opportunity to examine it. (Unless you're talking about the aftereffects of the boom, in which case a DC 18 seems way too high to determine that the "fireball" didn't actually set anything on fire.)

Also, mechanically... what does the amulet actually do for you? So you create an illusion of a fireball. Does that give you advantage on Intimidation checks against anyone who saw it? If it's just to make flashy booms, there's already a wand of pyrotechnics

The idea of an item that helps someone pretend to be a spellcaster is a cool one, but it feels like there might be a better way to approach it

Quote from AntonSirius 

Also, mechanically... what does the amulet actually do for you? So you create an illusion of a fireball. Does that give you advantage on Intimidation checks against anyone who saw it? 

Don’t forget, it can replicate ANY evocation spell. Meteor swarm to cause mass hysteria, sphere of force to appear less vulnerable to your enemies, and spells like wall of ice to cut off an opponent! I will agree that the DC is too high though