One of many debilitating powers of a Beholder, the anti-magic cone will remove ("de-buff") any and all magic effects that protect or guard a character. The anti-magic cone also prevents a character from arcane or divine spell casting for 3 seconds.
Since a player will be stripped of Death Ward, Protection from Evil and other alignment or death magic protections, the possibility of being killed immediately by Disintegrate, or similar death spells, or affected by negative energy effects becomes highly likely unless the player wears an item with persistent Deathblock effect. Even with Deathblock, the odds of survival from repeated Beholder attacks becomes remote.
There is no save to the anti-magic cone. You can mitigate death effects with items with Deathblock and spell absorption and/or negative energy protections, such as:
- Mantle of the Worldshaper (5 spell absorptions)
- Sacred Helm (Deathblock)
- Scarab of Spell Absorption (50 spell absorptions, one-use)
- Scarab of Protection (12 spell absorptions, one-use)
- Pale Lavender Ioun Stone (up to 50 spell absorptions and rechargeable once unlocked)
- Silver Flame Amulet, Pendant or Talisman (Spell absorption and deathblock as it is upgraded)
- Beholder Optic Nerves (Beholder spell absorption)
Some classes create spell-like abilities that are NOT affected by anti-magic cones and may be able to use their abilities even if struck by an anti-magic cone. These include:
Beholders have See Invisibility ability. While Invisibility spells cannot fool a Beholder, the ability to Sneak may allow players to avoid a Beholder, or get very close to the powerful, but physically frail enemy, initiating an attack before it's 360 degree Spot check tells it that you are near. A side or rear attack avoids the anti-magic cone, which comes from the monster's central front eye.
As its name implies, the anti-magic cone is an actual cone-shaped AOE effect, fired off every 3 seconds (its duration is 3 seconds as well). Like any cone spell, it can indeed be dodged: very difficult to do so being that the cone is invisible, but skilled players can still do so simply by moving fast enough (Sprint boost/Monk speed recommended). Spell absorption items such as a Scarab of Protection, a Pale Lavender Ioun Stone or Mantle of the Worldshaper can also deflect the cone effects. Positioning yourself behind the beholder avoids this attack, where melee fighters can use Stunning attacks to hold it in place for the kill.
The following creatures have been confirmed to be capable of creating Anti-magic cones (there may be more - research continues - be on your guard).