The only Platonian without psychokinetic powers, a jester abused by his masters who leaves with the Enterprise crew.
Alexander is a dwarf who serves as the court jester to the Platonians, a group who live on Platonius according to the ideals of ancient Greece. In Plato's Stepchildren he alone lacks the psychokinetic abilities that his masters gained from a mineral in their food, and he is treated as a plaything.
When McCoy finds that the powers come from kironide, Kirk and Spock gain the abilities themselves. They offer them to Alexander, who refuses, not wanting to become like his tormentors, and instead leaves Platonius aboard the Enterprise. He was played by Michael Dunn.