The Collaborative International Dictionary of English v.0.48:

Phantasmagoric \Phan*tas`ma*gor"ic\, a.
   Of or pertaining to phantasmagoria; phantasmagorial.
   --Hawthorne.
   [1913 Webster]

WordNet (r) 3.0 (2006):

phantasmagoric
    adj 1: characterized by fantastic imagery and incongruous
           juxtapositions; "a great concourse of phantasmagoric
           shadows"--J.C.Powys; "the incongruous imagery in surreal
           art and literature" [syn: phantasmagoric,
           phantasmagorical, surreal, surrealistic]

Moby Thesaurus II by Grady Ward, 1.0:

39 Moby Thesaurus words for "phantasmagoric":
   Barmecidal, Barmecide, airy, apparent, apparitional, autistic,
   chimeric, deceptive, delusional, delusionary, delusive, delusory,
   dereistic, dreamlike, dreamy, erroneous, fallacious, false,
   fantastic, illusional, illusionary, illusive, illusory, imaginary,
   misleading, ostensible, phantasmal, phantom, seeming,
   self-deceptive, self-deluding, specious, spectral, supposititious,
   unactual, unfounded, unreal, unsubstantial, visionary