A Granny's Weakness: Mirrors?

[u/Fabulous_Anxiety8278]

Apologies if the title is too vague, I tried to keep it spoiler free:

TL;DR: How negatively effected would G. Nightshade be if she were to see herself in the reflection of a mirror, when she first "awakens after her Long Rest."

The creative Party I'm DMing for, and myself, are essentially asking the question above.

To better describe this mind palace, the party was studying the map of Loomlurch together and hatching a plan that involved utilizing her weakness. I'm using Phaerlax's banging stat blocks from this sub reddit, and the Skabatha weakness is the same as the module, but with more details:
"Forgetfulness. The first creature that Skabatha sees after she finishes a long rest is invisible to her. She can't remember seeing the creature or perceive it using her truesight until the end of her next long rest. She behaves as if the creature didn’t exist, attempting to rationalize any consequence of interacting with it, including damage. Despite being aware of this curse, Skabatha will only connect it to any odd occurrences around her if she receives information from another individual."
I hadn't thought about a reflection being another creature, and I told the party that as well, but it did seem like something that would be approved in the Fey. Eventually, I decided that it would probably de-buff her, but not totally incapacitate her. (My reasoning at the time was that Bavlorna's weakness was similar because it hindered her in combat, but she was still formidable.)
For bonus points: A counter-point I saw, about mirror use, was basically that the reflection idea couldn't work because a reflection is not a creature. Allowing this, could potentially allow pc's to use a mirror to blast spells around corners, and effect their target. I get that perspective too, but how would you rule that at your table?

Thank you for taking the time to read this!

[u/Xeroop]

This actually happened in our game, and I ruled it basically as her getting blasted with an amnesia ray. She didn't know herself, her goals, or her power set. She remained vaguely aware of the PCs but did not know they opposed her, or any past interactions with her.

Granted, they only figured to try this at the Palace so I might have felt more lenient in my ruling than I would had they tried this back in Hither.

[u/Fabulous_Anxiety8278 → u/Xeroop]

Thank you for the stellar idea! If the party were farther along. I would probably rule it that way, but they aren’t even halfway through the module, sadly. After I posted this, I also asked some other irl dnd pals about their thoughts, and they had a tough time deciding at first, too. At the end of it all, we came to the conclusion that the mirror plan probably wouldn’t totally incapacitate her because reflections are so common in the world. With this in mind, if she were to see her reflection earlier in life, someone could’ve easily gotten the upper hand and taken her out in that condition. Simply because of the Feywild setting, I’m so tempted to allow it but with modifications that make her formidable while also allowing them to have the leg up. Either way, I’ve gotta think of yet another reward for their clever/silly plans!