Vartigan

'Vartigan' is the decibal-level detector that eliminates students with lasers if the noise level gets too high. The school system doesn't use 'Vartigan' anymore because of lawsuits. It also shoots you if you say something stupid. Teacher's have to 'calibrate' by registering their voice with 'Vartigan' so it wont shoot them.
This whole idea was a pseudo-dream I had during study hall.