Yes i have also done stuff like that i once entered a chat with the nickname zombie and always typed "uuuuuuuuuuuu" at the begining people ignored me but then i started putting myself in the middle of other peoples conversations and did "uuuuuuuuuu" they called me a lot of bad names but eventualy they became so annoyed that they left the chat.

Eventually i was always getting kicked out of that chat by the "GURUS" who were the big heads around that place...but i had a plan prepared one day me and another friend of mind entered in the chat room with 30 nicknames each. There were 60 zombies in the chat and we did "uuuuuuu" randomly they couldnīt kick us all out and decided to create a chat room called "U" for zombies, that was the most annoying thing i ever did in a chat room.