Sure, it's small and slow now, but that's only until it becomes self-aware and starts upgrading itself.
"The DIY Laser Guy," known by the YouTube username styropyro, posted video last month of what's he's calling his "most terrifying laser creation as of yet." The Laser Guy picked up a simple remote-controlled spider robot, which looks plenty scary on its own, ripped off one of the upper appendages and attached a "death ray laser" to its head. The result is a remote-controlled bot that can not only pop balloons with the intense heat of its laser, but also set stuff on fire. Check it out:
Sure, it's really only doing damage to small stuff in the video, but imagine that laser firing into your unprotected eyeballs, or setting your bedsheets on fire. Or better yet, imagine dozens of these little monsters skittering all over your house, setting things ablaze and melting your cat.
Sure, it's remote-controlled now, but we all know it's only a matter of time before it starts learning. If you need me I'll be busy constructing a spider-altar for our new robot overlords.