Symbols are funny things. I'd recommend downloading a copy of the Principia Discordia and looting the hell out of it myself. It is inherently absurd by design, but it has more than its fair share of stylish symbols.
Freemasons◊. Not really obscure though.
This one◊ is for the Thule Society, apparently.
Oh, of course. I suppose an over-conspiracy's symbol isn't complete without a reference to the Freemasons. Regarding the Square and Compass, I'd suggest it would be best simplified into an imperfect diamond, wherein the bottom point is ninety degrees, and the top is less than ninety degrees. (To the best of my knowledge, there is no canonical measurement for the compass' angle in the Masonic emblem.) There's plenty more Masonic symbols around; we collect the bloody things like a Kleptomaniac Hero collects doodads. Without going into detail, I suppose you could use a right triangle, with sides of 3, 4, and 5, as well. (The units don't matter, only the proportions.) Oh, and columns. Trust me on this: stick a column on each side of the symbol, maybe holding up an archway.
EDIT: Oh, and the Eye of Horus. Not one of ours, but it's definitely a classic for ominous, mystical conspiracies in general.
edited 24th Mar '11 10:14:28 AM by KillerClowns
Anyone know any good symbols associated with conspiracies, ancient or otherwise? I'm making up a conspiracy that's run by a rather Genre Savvy leader, for for entertainment value said leader is making his conspiracy's sigil a combination of other real-or-imagined conspiratory symbols. The ones I know of off the top of my head are The Illuminati's eye-in-pyramid, and the Ouroboros (serpent swallowing its own tail), which I can't actually remember what it's associated with.
Anyone know any others? The more obscure the better.
Really from Jupiter, but not an alien.