It's my opponent turn. I have Prophet of Kruphix on the battlefield, which means I can play creatures as though they had flash.
I play Hypnotic Siren with bestow to gain control of Boonweaver Giant in response to the triggered ability. (I can do this during my opponent's turn because I control Prophet of Kruphix.)
Does that mean that the stack looks like this?
TOP Hypnotic Siren \ | / Spectra Ward | 1 2 | | \ Boonweaver Giant / BOTTOM
Will I gain control of Boonweaver Giant, and then it gets the Spectra Ward Aura under my control?
Can someone tell me whether there is a mistake in this play?
The rulings on Hypnotic Siren say:
Gaining control of a creature doesn’t cause you to gain control of any Auras or Equipment attached to it.
which does not apply to this situation because Boonweaver Giant does not have any Auras attached to it when I gain control of it with Hypnotic Siren.