Most dangerous code written by my friend

I haven't written anything particularly dangerous, as in viruses, SQLI exploits, trojans or anything of that sort. The most dangerous software I've written could possibly be used for denial-of-service attacks on the host computer. However, that is because they are extremely resource-intensive in terms of both processing power and memory consumption.

So by that margin, my C Mandelbrot Set movie renderer would be my most dangerous software, as it can routinely lock up a computer for up to 5 minutes at a time, eating up more than 2 to 3 GB of RAM while having an average CPU consumption of 64%.