At Least It’s Not Glitter

I'd get a box and cover it in birthday wrapping paper to make sure it was stolen. I wouldn't put my address or name on it in case they realize later and come back for revenge. Then I'd fill the box with thick blankets and cheap toys to make the weight. They'd rip into the well wrapped layers one after another flinging them away not realizing the nearly invisible company they had brought into their lives.

Bugs of all sorts, lice, fleas, ticks and even bedbugs if I could find them. If lucky I could even get miniscule baby roaches to add to the fun. The pirates will sit there in disappointment, bemoaning the cheapness of their ill-gotten gains. Days, or weeks maybe even months later they'll realize their infestation. They'll be sent home from school or work in tears with itchy scalps and red bumps on their skin. Their house will crumble around them from insect damage. They'll be pulling up carpets and washing everything they own over and over. As they spend all their money on exterminators they'll wonder how this happened to them.

They'll never know how it happened, never suspect that it was me. Even if they did what could they say, that the stuff they stole was infested. I'll lose nothing but some cheap plastic toys and some thrift store blankets bought especially for this purpose. Cheaper than most of the booby traps I see and more insidious. Only drawback I see is that I don't get to witness their reaction but I can imagine it and smile.