Mini Barf will eventually exhale a blast of stinky breath, which has the very unfortunate side effect of making all members of your party start crying, which significantly reduces your accuracy. However, this only affects accuracy of physical attacks, so use your PSI attacks if you're crying. But before Mini Barf blasts you with stinky breath, use physical attacks to conserve PP. Use Healing β or healing items to cure the crying if you wish, but keep in mind that the Mini Barf can just exhale stinky breath again. Healing the crying might really just be a waste of time.

Jeff can act as a supporting unit, healing Ness and Paula as necessary. If Jeff has Bottle Rockets, or if anyone has bombs, you can use them against Mini Barf to do him some significant damage.

Once Mini Barf is gone, you can continue on up the ladder and head toward Saturn Valley.