Slan

The race of persecuted super humans in the A. E. van Vogt novel of the same name. Slans, depicted as the next stage of human evolutionary development (homo superior), are intellectually superior – and the ones who had [[tendrils]] in their hair were natural telepaths. In the book, they were being hounded to their deaths by mere homo sapiens, presumably because the poor saps didn't want to be replaced by the pure sups.

Fans identified easily enough with slans as a persecuted minority because of the reactions they frequently got from mundane society merely for reading that Crazy Buck Rogers Stuff – but not to the extent that they believed fans where superior beings. Degler and his Cosmic Circle also alluded to fans as the “star begotten” – a similar concept but a reference to a much earlier H. G. Wells story of that name, in which advanced and misunderstood humans were the result of Martians inducing mutations in the human race via cosmic rays.

Degler’s plan included love camps in the Ozarks, as mentioned elsewhere in these fan terms, where the slan-like star begotten race of fans could go to breed the race that was destined to rule the sevagram. But the many fans who effectively laughed Claude and his Cosmen out of the microcosm, even including some of his major detractors – particularly as they got older and fatter and less attractive to the opposite sex – were later inclined to admit that while the notion of fan superiority should continue to be looked upon with suspicion, maybe they’d been a bit hasty in rejecting those love camps, which might not be such a bad idea after all.

Contributors: Dr. Gafia

A later take on it: "Fans really are slans — they're just not very good at it…"

from Fancyclopedia 2
(vanVogt) Superman produced by mutation from humans; the word is sometimes used to mean any superhuman mutants, but in the story they were the children of Samuel Lann and their descendants. These folk had "tendrils" in the hair that gave the power of telepathy, with greater than human intelligence, strength, and endurance as a byproduct of their real advance: a nervous system of transcendent resilience and complexity, adapted to the demands of mechanistic civilization. Because the central character in the story was a youth in unsympathetic surroundings, and because of the obvious similarities to fans' dreams of greatness, the unserious claim to slanhood became the Third Fandom parallel to Second Fandom's half-serious star-begotten claims.
from Fancyclopedia 1 ca. 1944
(van Vogt) - A superman of a type different from Homo sapiens by mutation, the most noticeable characteristics being two hearts, tendrils in the hair which give the power of telepathy, and greater intelligence than H sapiens. There are tendrilless slans who lack the telepathy tendrils because their genes were tampered with, but will eventually have true slans for descendants. Slans were natural mutations, freaks who happened to have advantageous features, the children of Samuel Lann. After being beaten back by H sapiens in one war, they established themselves on Mars and worked into control of the Earth government. Because the central character in the story was a youth in unsympathetic surroundings, and because of the obvious similarities to fans' dreams of greatness, the unserious claim to slanhood has become the Third Fandom parallel to the Second Fandom's half-serious Star-Begotten claims.