lol, i always download those
DON'T PANIC!!! :-D
i drag them into notepad and look @ how they're made. Most just try to do a low level format or somthing, nothing too interesting, a few do a netsend to everyone on the network going, IF YOU READ THIS YOU ARE A MUNCHKIN or somthing, and then reload themselves so you keep getting the messages until the sending computer restarts or runs out of memory, some deltree windows on restart, and some simply open a web location where they have the proper virus/trojan
