This is actually just a generic legendary, but I got it when in Boomkin spec so it comes under Boomy for me. I got it from my Farondis cache.
Not sure when a legendary that does "30% increased damage when target is over 90% health and heal you for 100% of damage done" can be used in any way that is useful... now it if it was an execute that would be more useful (ie 30% increased damage when target is under 10% health...) but it's another one to add to the collection. I doubt this one will ever leave the bank.
I must admit, that it was only 8 days since my last legendary. Hmm. How long till the next one?