at ~1:45 my opponent drops a hatchery at my natural and cancels it after a few seconds only to immediately start an evolution chamber. I killed it after it finished and used his delay in spawning pool to pull of a bunker rush that I slowly used to mech my way to victory. They gave me some nice BM at the end too!
When this happened last week the person I was playing did the same trick but dropped a spine crawler which broke my wall off. I've been playing SC2 for 10 years now and I've never actually seen this strategy? hack? bug? What is this?