"She is," Kel Aran assured me. "She's older than the Earth was. The silicic beings didn't reproduce. Only three of them appeared, when life was born on their planet. But they were immortal—practically.
"The three of them lived together, for billions of years. They dominated the far more numerous carbon-life, and came to rule the planet. But then there was some kind of triangular quarrel. I don't know the details—Setsi never mentions it, unless she is very drunk. But there was jealousy. One killed another. And Setsi killed the survivor, out of revenge. And she has been alone for a long, long time."
"Drunk?" I stared at the lean Earthman and the thing like a glass toy in his hand. Kel Aran nodded.
"Yes, Setsi shares a weakness of Zerek Oom. Her metabolism is stimulated vastly, but rather erratically, by the assimilation of any carbon compound. Gasoline would do, or sugar, but her favorite is alcohol—Watch!"
He laid the bright rigid form on a table in the galley, and poured a few drops of rum into the palm of his hand, from Zerek Oom's hoarded bottle.
"Setsi, old girl!" he called. "Want your grog?"
A brighter lustre lit the great dark eye. I saw a quick vibration of a thin transparent membrane that stretched between the crystalline arms. And a whirring voice answered him, softly melodious as the cooing of a dove:
"Oh, she does, Kel! Setsi dies for grog!"
He stretched out his hand, and the brilliant thing came to surprising life. The fluttering membranes extended. The creature leaped into the air. A dancing shimmer of color, it flew to Kel Aran, alighted on his hand, and sucked greedily at the rum with a mouth on its under side.