Unidentified Life Forms have a decent defense against your physical attacks, but have a rock solid defense against elemental spells of all sorts: damage will be reduced to zero. You can get around this, however, by making use of the Force spell which actually deals physical damage. That should be able to wreck these guys in one turn. Equipping a Magic Ring or other variant will also allow physical attacks to hit. As for their offense, they'll almost always use a physical attack of their own. They do have the Fear and Shine spells in their repertoire though.