Make Your Own Star Trek Phaser
Countless Star Trek fans have dreamed about owning their own phaser, and while Wikipedia lists it as a "fictional weapon," one enterprising (rim shot) gentleman decided not to let anyone else tell him what can and cannot be real, and transformed a 1994 Playmates replica of the phaser from the classic "Star Trek" series into a 320mA – 465mW laser device, complete with appropriate sound effect.
He's even got a tutorial to help you build your own, and while this may not be as dangerous as the "real" thing -- e.g. able to burrow tunnels through solid rock and disintegrate hostile aliens -- there's a video of the guy popping balloons with the beam, so it's not a joke, particularly if you shoot it into someone's eyes. Remember: Once you add actual lasers to a toy, it's not a toy anymore, so don't point it at any living things, ok?