Possibly the best fan of science fiction from CCosgames's blog

Forrest J. Ackerman, possibly the best fan of science fiction who ever lived, attended the primary ever World Science Fiction Convention,   Etaya.com   or Worldcon, in “futuristicostume.” 

Ackerman “strode the streets searching like a proto-superhero” talking Esperanto together with his pal and the dressmaker of his dress, Myrtle Douglas.    Power Rangers Costume     He changed into the primary sci-fi fan to wait a convention in costume.