Rae sent out a maze of webs as she darted around the room, terrifying the students whose eyesight was good enough to keep track of her.
"That should do it. She built an obstacle course around your existing course, made of sticky spider silk. If they catch one strand, it will ring the bell in the middle of the room, and if they catch a bunch, they will just end up tangled." Karl explained, with a gesture toward the bell, which was now the focal point of dozens of strands of silk.
"How much light do you need to track movement?" The teacher asked.
"Zero. I can detect movement decently well even with absolutely no light, but in this room, and in their uniforms, it would be nearly impossible for me not to detect them unless they were truly invisible." Karl explained.
"Jeff, activate your stealth skill." The teacher instructed, and one of the boys seemed to simply vanish into the shadows.