GrissTheGnome
Explorer
During the first month of the blog we posted an article about designing boss encounters with "Phased Boss Fights." Borrowing an idea from video-games (mainly World of Warcraft boss fights, and my more recent experience in Dragon Age Inquisition), in my own game (we were in high level D&D mode at the time, and making fights with bosses last longer was something I was toying around with), with rules how to apply it into D&D. I revisited the concept, which Enworld posted on a 5th edition fan round up thread as the Frozen King article. Anyway here is the original for your enjoyment.
http://forgotmydice.com/index.php/2015/11/23/phased-boss-fights/
http://forgotmydice.com/index.php/2015/11/23/phased-boss-fights/