I just found a GIF on Reddit that might freak out some of your co-workers, and you don't have to do much.

Just head to THIS LINK, and leave it open on your screen. That's all you have to do. If you work with someone who is freaked out by creepy crawling things, you'll be sure to freak them out with this.

Spoiler for anyone who doesn't trust me, it's a GIF of a spider walking across your screen.

Try it! For more fun hook up your webcam to capture their reaction, be sure to send me a link if you do this!