A species whose members are colony creatures able to divide their bodies into three independent parts, known from Commander Bem.
Pandronians are colony creatures: each individual is made up of several parts that can separate and act on their own, then rejoin into one being. They are proud of this ability and consider themselves superior to species that lack it.
In the animated episode Bem, the Pandronian Commander Ari bn Bem joined the Enterprise as an honorary observer for a planetary survey. He repeatedly disobeyed orders, slipped away from the landing party by dividing his body, and secretly studied the crew as part of his own evaluation. His actions put James T. Kirk and Spock in danger on a world watched over by a powerful being, and Bem finally learned that his assumptions of superiority were mistaken.