This says a lot about the state of the lore. It was widely thought that in 8.3 Mythic N'zoth there was a secret phase at 25% health, since it seemed so unrealistic that you could actually burn down N'zoth before everybody died. Everybody thought there was a mythic only ending that just never ended up happening. The big mythic only world first surprise just didn't end up happening, the mythic only surprise was a burn phase. Really funny times.