"Blue Sky" (also known as Big Blue, Blue Magic, or Fring's Blue1) is the street name which has been coined for the notoriously potent and 99.1% chemically pure crystal methamphetamine manufactured by Walter White and Jesse Pinkman.
One of the most popular fanfictions in the Portal 1/2 fandom. Was written in 2011-2012 by wafflestories and can be found on FanFiction.net. It has 15 long chapters and is very popular, even being referenced in the Portal 2 Unauthorised Musical and many other media across the fandom.
Last night I read the fanfic "Blue Sky", it gave me a feels trip I wasn't prepared for.