My ultimate strategy !!!

but then the russian zerg will just send mass waves of units at you and push you back.

 

When I get Queens, I parasite workers that are on gas (players don't check on them as often) and critters, because nobody ever suspects the critters. And yes, parasite + Kakaru = awesome spy. ^_^

 

Don't kakaru have a really bad sight range though?
The worker thing is great though. I remember doing that a lot. Cause there is so many workers all right there and most people don't suspect it.

 

I was VSing my friend 1v1 and he didn't have turrets nearby his minerals so I flew a few Queens over while he was busy microing against the Hydralisks.
He was busy getting a small wave of Cloaked Wraiths when I ran in and used every Queen's Spawn Broodling ability on an SCV and then I rallied all of 'em onto the Command Center and Infested it.

In chat after he killed my Hydralisk squad he complained how slow workers got minerals until he said, "Oh." when a bunch of Infested Terran slammed into his Bunkers.

 

It rocks with the zerg mission where you have to bring duran to the 5 beacons!