Sorry this is Badhabbit91, I just swapped to my brothers account because I can only post three messages an hour, thanks a lot Gamefaqs, but anyway, where in the Catacombs do you have in mind?
A safe place, to avoid traffic would be the room before the first bonfire. So if you are at the bonfire, kill the two skellies in the first room, head through the small corridoor on the right, kill the 3 skellies in that room and that is where it will be.
However, this may be rough on your level 20 depending on what equipment you've got so we can try right next to the bonfire if need be.
There was also a griefer with a lightning weapon and a lightning avylen that was roaming about a few hours ago. Hopefully he's gone. --- ,=,e