Arachno

Arachnos aren't too hard, but they will definitely eat the average newbie. They deal out a truckload of slashing and bleeding, unless you have Ultraclot. Dodging is a good defense against their attacks: for this reason (along with the fact that they can't take hits very well) you will often find people fighting them naked. Their contract payouts are good, $500 per arachno which is the same as yetis.

You can find arachnos in the subsewers, underneath the Bug Queen. (Kill her to get by.)