We don't have synonyms for swamp gas yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are swamp oak, swamp gum and swamp bay.
(n) :
(ufology, sarcastic) A skeptical explanation that is provided in order to debunk a UFO sighting that a believer regards as ludicrous, illogical or disingenuous.
(n) :
(ufology, sarcastic) A skeptical explanation that is provided in order to debunk a UFO sighting that a believer regards as ludicrous, illogical or disingenuous.