Pranks
IRC Pranks
There are a few IRC pranks, none of these are damaging to your computer, but if you are caught by them, your own annoyance will likely climb.
Channel Zero
The Channel Zero prank is about the oldest IRC prank out there, 'invented' somewhere around 1990, when the design of IRC changed from fixed channel 'numbers' into the design we see today: channel '#names'. By default, everyone did (and still does) join channel 0 when they first connect. You know this as the network 'status tab'.
The prank; Someone tells you to type or click this:
/join #10,000 /join 0 /join #h,e,l,l,0
and many other variations on the theme.
If the user types those commands, or clicks the link, they leave all channels that they were in.
TheNick (Mibbit@mib-47B6034F.some.network.com) has left #TheChannel (Left all channels)
The reason this occurs is that, by design, joining the numbered channel 0 (channel zero), that you are already a member of, causes you to then leave every other channel.
It is not a bug, but a backwards compatibility issue. Some clients try to block this behavour, to various levels of success.
Ctrl+W
The Control-W prank is fairly new, as it best works to users of web based IRC clients and modern browsers.
The prank; Someone tells you to do this:
Press Ctrl+W Press the Control key, and type W
and many other variations on the theme.
If the user types these commands, they disconnect from the network.
TheNick (Mibbit@mib-47B6034F.some.network.com) has left #TheChannel (Quit: TheClientDefaultQuitMessage)
The reason that this occurs is that, by design, most web browsers have the Ctrl+W key pattern mapped to Close Tab.
It is not a bug.
References
General Google search results for Numbered Channels. [1]
Section 4.2 Numbered Channels. [2]