Take the 2-minute tour ×  I played a 3v3 last night with mostly
novice players. It was PTT vs. ZZT. One of my opponents got
sight in the rear of our bases and started flooding the place
with Roaches and Hydralisks via Nydus Worms.  We were able to
fend off this attack with our various defensive units.
Unfortunately, these had been up at the choke point and not
really prepared to run back, which took some time so the Zerg
were able do to some serious damage. What's more, the Zerg were
able to retreat handily back to the Nydus Worm and live to
harass again a minute later somewhere else.  What are some good
ways to:    • Detect an incoming Nydus attack quickly to react?
• Destroy the incoming Nydus Worm before it completes building?
• Take out the Nydus Worm after the units come out so they can't
retreat?   • Prevent the whole thing from happening in the first
place?  In this case I don't think denying sight would be
possible, considering they had a Terran player with no qualms
about using Scanner Sweeps.  M