This strategy will make your opponent's massive base crumble into dust.

-Build until you have 7 probes, and make him build a pylon.
-Build more probes, a Gateway, and an assimilator
-Continue building more probes, pylons, and gateways.
-Build a cybernetics core.
-Build mass dragoons.
-Build a citadel of adun, templar archives, and 2 stargates.
-Upgrade hallucination, build some templars, and build an arbitor tribunal.
-Research recall, stasis field, and arbitor energy.
-When you have 4 arbitors, and lots of dragoons, make your arbitors hallucination your arbitors, so you have 12 fake ones, and 4 real ones.
-Hotkey each of your real ones, and send the fake ones in first.
-While your opponent is busy fighting the fake ones, send the real ones in strategic locations, and recall all of your fudgin' dragoons.
-If your opponent has lots of units killing your goons, just stasis field them.