Yesodite

The Yesodites or Yesodi were a species of jellyfish-like aliens from the planet Yesod. They released toxic radiation and were able to protect others by confining themselves to a pressurised metal suit. (PROSE: The Ice Garden) They evolved from the Malkuthites after they altered their biodata so they could live on Yesod. (PROSE: The Long Midwinter)