Anti-Crystal Area

An «Anti-Crystal Area» is a rare trap in Sword Art Online, that, as its name suggests, prevents the usage of crystals to heal or teleport.

Background
As the name suggests, this kind of trap prohibits that use of crystals, disabling the players from teleporting and healing themselves with crystals in battle. While crystals can not be used, other items such as healing potions can be used but those take longer to use.

The trap is sometimes activated in random dungeons rooms. It also occurs in the boss rooms of the 74th and 75th Floors, and implies that the boss rooms in the remaining floors are also Anti-Crystal Areas as well.

Victims caught in Anti-Crystal Areas have always resulted in many deaths. One trap found by the «Black Cats of the Full Moon» easily claimed all its members' lives but Kirito, including its leader who did not partake in the battle but had committed suicide upon hearing the death of his comrades. «The Gleam Eyes», the boss of the 74th Floor, killed three members of «The Army», one of which was the leader of that party's squad, Cobert. «The Skull Reaper», the boss of the 75th Floor, massacred ten players who tried to examine the boss room, and easily claimed the lives of fourteen more in the second battle.

Área Anti-Cristal