Rupert Giles used this blue hypnotic crystal, split in the center, against his own better judgement. The Watchers Council established a rite that every Slayer who reached the age of 18 years had to pass. Buffy Summers arrived at this date and thus he was compelled to hypnotize Buffy by making her look into the crystal. While she was hypnotized, he injected her with a product which inhibited all of her special capacities as Slayer.