The old alpha tribe on my server brought 11 gigas to our front door 6 months ago, 5 at first and then an additional 6 gigas after we wiped the first wave. We marched outside to face them in certain death with the Rex bloodline we managed to muster after two months of being on the server. We hand endured over 5 hours of rocket quetzals slowly breaking bits of our base down to the foundation. All of our riders had 3 metal spikes on their hotbars. We charged them head on and they charged us. We manged to surround a few of the gigas and do a pincer move with our spikes, essentially trap and ping-pong most of their gigas off our spikes and focused all of our aggression on one giga to enrage it and knock all the other giga riders off when their mounts also enraged. We did not lose one single rex on that first assault. The 6 extra gigas killed two of our rex's. We spent the next week destroying all of their satellite bases all over the map and finishing them off in an 13 hour siege of Volcano crater. This was on official 25. I will never underestimate the power of rex's, planning, and teamwork after that battle.