Rotworm Caves

Rotworms are good for players of level 8 with a vocation, they give a decent XP and loot, but if you're a mage or paladin, keep the distance.

You need a shovel to open the holes.

You can also find rotworms spread all over the mine shafts, but they are found with other creatures as well, increasing the risks for a low level.

Rotworms are found in the katana quest too.