As of the version 0.4_20120320 (March 20th 2012), all mobs were removed from the game. They will be re-developed in Lua later.
Total Mobs: 4
Description: Oerkki are hostile mobs which appear in very dark places. They do not spawn above ground at night. They hover around and cause damage. They disappear if clicked a few times.
Description: Fireflies are currently useless. You can pick up and release them that's about it.
Description: Rats can picked up and released, they also can be cooked and eaten to restore health.
Title: Dungeon Master
Description: An incredibly powerful mob that shoots block dissolving fireballs and is very durable. They take about 15 hits without a weapon. Wooden Swords take 7 hits, Stone Swords take 5 hits, and Iron Swords take 4 hits to kill them. Their fireballs make a 4 block crater. Unlike the Oerkki, swords are more effective than your bare hands when fighting Dungeon Masters. Touching them causes you to lose 1/2 heart and getting hit with a fireball gives 4 1/2 heart damage. Dungeon Masters have animations when they walk and can be seen at different angles. Dungeon Masters spawn underground and can damage peoples homes. They can destroy any block including chests, furnaces, and locked chests.