From RoboticonWiki

The Challenge

Vampires, Werewolves and Robots, Oh My! Monsters have overrun the the city! This is far too dangerous for regular police to handle, and Buffy is out of town. In their desperation, the townsfolk have turned to your team of evil geniuses to rout the horrors!

As everyone knows, werewolves and real vampires (not the sparkley ones) are visually indistinguishable from normal human beings. There is, however one trick by which they can be identified: their reflections. In a silver mirror, vampires have no reflections, and werewolves appear in their lupine forms.

In order to mitigate the damage, the mayor has quarantined the downtown area. Your robot will be stationed at the exit to the quarantine area. The entire quarantine area will be blocked on three sides by 3.5" black walls. The fourth wall will be a 6" high white wall that will represent the mirror. Parallel to the mirror there will be a line of plastic bowling pins representing the citizens fleeing the area. Each pin will be exactly 1' from the wall. The pins will be at least 6" apart as there is a strict anti-crowding policy in effect. The limit of the field will extend 1' further from the mirror than the pins. There will be at least one foot before and after the first and last pins respectively. The colour of the wall parallel to each pin will indicate the type of entity present. A black wall section indicates a normal reflection. A grey section indicates a werewolf reflection, and if the wall remains the background color (white), then there is no reflection; you've found a vampire!

Your robot can slay any citizen you suspect of being a monster by knocking over the pins. This can be accomplished by any means you like. Try to get all of the vampires without killing the humans! Also be aware that werewolves can only be killed by silver bullets. There will only be one werewolf and you will only have one silver bullet. In order to use said silver bullet, your robot must emit a single beep indicating that the bullet has been loaded. It will be used on your whatever entity is knocked over next. Any beeps after the first will be ignored.

Every vampire that is alive at the end of your run will kill one human. You receive one point for every living human. There will be at least as many humans as vampires. There will be a maximum of ten humans. Killing the werewolf gives 2 bonus points.

Your run will last up to three minutes. You may choose to end your run any time before this. You are restricted to the pieces that come with your NXT kit. Sensors are limited to one touch, one light/colour and one ultrasonic sensor. Sound sensors are not allowed.