Ectoplasm

What's ectoplasm?

Is ectoplasm a real thing?

He saw again clearly enough[…]the doctor’s consulting room in the Avenida de la Revolución, visited for some drunken reason in the early hours of the morning, macabre with its pictures of ancient Spanish surgeons, their goat faces rising queerly from ruffs resembling ectoplasm, roaring with laughter as they performed inquisitorial operations; […]

Watching as the woman lifted her skirts and flung out ectoplasm, expelled it into a bowl, then brandished it around at her audience wildly.

Then came some hollow groanings from inside the cabinet. The Spiritualists sat up expectantly. "That's ectoplasm," said Ogilvy. "It always causes pain on emission."