Faerzress

Faerzress is a strange magical miasma that permeates the Labyrinth and interferes with the weave. It causes the following properties wherever it exists:

• The area is dimly lit. Motes of light occasionally twinkle briefly into existence like fireflies.
• Creatures have advantage on saving throws against divination spells. If a divination spell doesn't target a creature or doesn't allow a saving throw, the caster must succeed on a DC15 Constitution saving throw to cast the spell. On a failure, the spell is wasted with no effect.
• Any creature attempting to teleport into, within, or out of the faerzress-suffused zone must succeed on a DC 15 Constitution saving throw, otherwise they take 1d10 force damage and the teleportation attempt fails. Even if they succeed, the teleportation attempt can suffer a mishap as if the destination was known only by description, regardless of how familiar the destination actually is (see the teleport spell description).
• Portals and extradimensional spaces are disabled; items like the bag of holding and spells like arcane gate are disabled.