W32/Oscabot-F is an instant messaging worm that can exploit users of AOL Instant Messaging clients.

W32/Oscabot-F connects to a specific channel on an IRC service and waits for an attacker to instruct the bot to send messages to contacts in the infected user's AOL contacts list. The message will read:

"lol have you seen this?"
The word "this" is a link to the W32/Oscabot-F executable on the infected computer.

More information can be found at this Sophos page.