When attached, it ceases to be a creature and functions as an equipment, granting the equipped creature its abilities, stats, or other benefits
Bloodbraid Elf / Deathrite Shaman If you've only started playing or following Modern recently, you might not realize that there was a very long period of time when Jund was the best deck in the format
Its not gone forever, you can pay three mana and transform it back into Ojer Kaslem but only if you have at least ten permanents in play.
Playing this on turn one will win you a lot of games, but it is a pretty bad top deck late
Interestingly, it's never been the same guild
There were no good answers to a Frenetic Efreet, only answers that worked half the time, so as long as you weren't far enough behind that he was ignorable the Efreet was always effective