From Guild Wars Wiki
- Concise description
Environment Effect. While in the area, every spell cast by a foe causes 10 Overcast.
- This effect is found in the Elite Mission Urgoz's Warren and is caused by Twisted Bark in certain rooms.
- Spells that already cause overcast (e.g. Ether Prodigy) will not cause twice the overcast while under this effect. [verification requested]
- Glyph of Energy is an optional skill which can be used to mitigate against the overcast.