In "Deja Q," Q is made human and transported to the Enterprise. Just prior to his arrival, an unusual noise is heard on the bridge, which neither Data nor Worf can identify.
Does anything state what this noise was? Was it a "portal" opening from the Q Continuum to the normal space-time continuum?
The script isn't especially helpful. I've edited out the dialogue.
In the background, a strange noise... it begins low... more like a million voices than a million machines... It gets louder... The sound continues to grow... and seems to surround the ship... they react... almost deafening now... The sound swirling inside and all around... ends with a slight POP. Q APPEARS, naked, suspended above everyone, as though held by an invisible puppet.
In context, it would appear to be the sound a Q makes when you forcibly remove their powers, turn them into a human, strip them buck naked and shove them headfirst through a space hole.
