[adamkad1]

If people are vehemently against Spirit Mirror being visible through Mysterious, then my suggestion would instead be to actively nerf Spirit Mirror. Another idea I had aside from allowing it to be broken via physical damage is that Spirit Mirror could instead confer a different buff with a 5-10 round CD, costs 3m. 75% Projectile-damage retaliation for 3~ rounds. Your opponent may see it but they'll be disincentivized to attack you at all if they're susceptible to it for as long as the buff lasts or provide some damage value if they choose to attack you multiple times during the buff, but this gives the opportunity to work around it either through the Mirrored enchant to mitigate damage taken, removing the buff knowing it's there, or avoiding Projectile attacks if possible while it is active. Thus giving the item counterplay.

Magic mirror being something that's more than one and done is nice idea.
Also ye mysterious/mask of metal too good