Mystery Chat Spam

For a while now, my minecraft server has been getting the text "Awooooooooooooooooooooooooooooo!" in chat. I can't seem to find where or what is producing it, and searching this doesn't really give any results.

Anyone got any idea where it's coming from?

Bukkit-1.4.2-dev

Edit: DERP It's part of the Mobs plugin. *Facepalm*

Since it doesn't seem to be anywhere on the net, best to leave this bit around, in case anyone else is baffled at first.