NGC 1999 is an abbreviation for Nigga Gone Cold 1999. This is the name of a particular Nebula in space that looks remarkably similar to some thuggish black dude turning his shoulder around like some shitty Tupac knockoff album cover. On mushrooms is key in understanding "an NGC" phenomena. Hip hop.
"So many niggas so much ice, make it so much coooold"
"NGC 1999 is so cold that he make iceburg lettuce minus the lettuce"