Quote from Raoul9753 >>

What a shitty spell... 

Only usefull if the target has negative Wisdom mods, otherwise its just a level 4 fear spell unless the target somehow fgails the DC twice.  

I wouldn’t go that far. While it would be ideal to have the damage kick in right away after the first failed save, many creatures aren’t that wise. 

When 4th level spells are kicking in, a caster should have a DC in the 15 to 17 range. Assuming a spell save DC of 16, a foe with 10 WIS has a 25% chance of making each save. That damage can stack up in a hurry if the fight drags on, and the enemy is basically neutralized during that time.

(Edit: previously incorrectly stated that subsequent saves are made at disadvantage, but that only applies to ability checks)

Since it's a basic rules spell (freely available), I created an "improved" version of the spell, available in the homebrew spells section.

"You tap into the nightmares of a creature you can see within range and create an illusory manifestation of its deepest fears, visible only to that creature. The target becomes frightened until the spell ends. At the end of each of the target's turns, the target must succeed on a Wisdom saving throw or take 4d10 psychic damage. On a successful save, the spell ends. 

Phantasmal killer isn't stopped by its target being unconscious, and a creature immune to the frightened condition can still take psychic damage. 

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d10 for each slot level above 4th. When you cast this spell using a spell slot of 7th level or higher, the target dies instantly if the psychic damage would reduce it to 0 hit points (no death saving throws)."  

 + includes a 1d12 optional Table of Fears (flavor)

No, the spell lasts for 10 rounds.

hey, dnd's like, "why don't we make a 9th level spell that does the exact same thing and call it weird!" everybody will love it!

Weird is an AoE effect, and while it gets panned a lot for the double save like this one and low damage, it's got good range and, while the description doesn't explicitly say it, should have a lot of enemies wasting attacks on the phantasm the spell causes them to see. As usual, though, all the munchkins can see is how many damage dice they get to roll at a time.

The perfect spell to add to the repertoire of a villain/bbeg whose whole MO is to manipulate and gaslight people! :D 

It is a fantastic spell if paired with lvl 5 Bestow curse... if you've maxed your casting modifier then median damage to creatures with +0 wisdom is over 200, and +2 wisdom (or +1 vs +4, etc) is still 129.  

If only there was a spell that gives disadvantage to certain saves to compliment this....
oh wait, there are.

Doesn't this spell itself give disadvantage through the Frightened state?

No, Frightened affects checks not saves.

bro that's op... good... but freaky.

Why this isn't a Warlock spell is beyond me.

Why do you have to make Two wisdom saves? Shouldn’t you only make one? 

Nightmare Teller

this is a nasty spell

Quote from OniFeeZ >>

Can a mob be immune to the frightened status effect but still take damage from the damage effect?

Can you cast this on a mob multiple times and have a stacking damage effect?

 Since things with the same name don't stack unless they say otherwise, no it doesn't stack

What if a creature is immune to the frightened condition? Do they automatically succeed on the first saving throw, avoiding the spell all together, or do they roll as normal, if they fail, they ignore the condition, but gotta keep rolling to end the spell to avoid the damage. I compromised in one of my games by making so the creature took half damage from the spell since they were immune to being frightened, but what do y'all think?

Yup! If they're immune to being Frightened, then they automatically succeed the first save, thus not being affected by it.

This is certainly more manageable than its 3.5 edition version. In that edition, it was literally "save twice or die from fright".

This upcasts so well!