Iyaaran

In the mirror universe, the Iyaarans were a race capable of changing their shape.

By the 2340s, the Iyaarans had become worried about the actions of the Klingon-Cardassian Alliance and wished to see the Alliance destabilized. To this end, the Iyaarans sent Sestro to impersonate $𝜇$ and infiltrate the Alliance. (SS STA (The Traitor))