Definition of antimeme:
(n) :
(Internet slang) An image macro which intentionally subverts one's expectations by not including a joke; a meme antijoke.
(n) :
(memetics, science fiction) A meme deployed to nullify or protect against another meme.
(n) :
(memetics, science fiction) A unit of information that prevents itself from being spread, often by erasing itself from any mind that it enters.