When three or more allos meet up, the highest level becomes an alpha. He will be the one with orange glowing cloud on his back. Reducing the pack to only 2 dinos will remove alpha status from the highest level allo. This means it is usually easier to kill the weakest in the pack first and then the fight will be much easier. Multiple alphas can be created if a large group of allos form. However that are not invincible. Personally saw a group of 15 Wild allos with 5 of them being alphas get wrecked by a Lvl 80 giga. So even if you could somehow tame all 15, you would be far from invincible. A good step up from a carno, but they stand no chance against similarly leveled Rex or giga.
They say beaches are low resource/low threat areas right? WRONG! I used to live in one close to a cold region and some of those decided to run around the beach killing everything there. Fine, I hid from them in my tatch base and once they were far enough I thought I was safe, that until another freaking pack started doing the same. I hid my Dilo (Galinha Punk, my beloved only tame, great companion) inside the base and ran through the ocean to hide on some stones. And this was way before they cold spot me. Result: I had to hold my tears and watch in horror as they destroyed the little base I put on all my effort to build, killed my poor boy and kept going like it was nothing! Their levels were way too high, I couldn't fight them, but I was so sad I tried, died, couldn't respawn there cause I had no bed anymore, and couldn't get my stuff because they were near. Of course i waited until they went away, and of course wild dilos destroyed the rest of my stuff. I shall have my revenge!
These guys are everywhere in Valguero. My friend and I were gathering resources when I saw them I ran and remembered Ark's loading screen had a tip that said "You don't have to run faster then the dinos you just have to run faster then your friend" so I used my bola in my hotbar and got my friend. Moral of the story get bolas lots of them