Back in the merged mining days of bitcoin/namecoin, there was a lot of worthless namecoin around and you didn't exactly know what to do with it:

So I had the bright idea to go around collecting publicly listed namecoin addresses - bitcointalk signatures, github donation addresses, developers, you name it I think I gathered about 100 addresses

I wrote a bash script and put looped namedcoind to read my text file and send the minimum tx amount to a random address every second....

So that was running in a (detached) screen and I got busy and forgot about... for a few days...

Some folks didn't think that was very funny and called it an "attack"