Too easy to setup infinite damage OTK
You could always use the same method as for siren. Don't allow boomstick to target another creature that has the boomstick ability on it.
Maybe I'm missing something, but I can't see another OTK possibility.
hmm.... okay I see one more way, but its by no means "easy"
You would have to use living weapon to make a siren into a weapon. Endow that onto one golem. Then replace it with a boomstick and endow that onto a second golem. Then you would have to use SOR on both of those. The siren golem would sing to the boomstick and the boomstick would then make the siren golem attack which would reset sing ... and repeat...
Of course takes a trio at the minimum...
It takes 2 of these cards, a siren, 2 golems, a living weapon, 2 SoR, and probably a good shield to keep the sing from killing you at the same time...
Thats a 7 card combo... There are much easier OTK's to pull off.
Moreover, you have to have the 2 of these cards in play on the previous turn since permanents don't enter play readied.