Okay so on top of them getting an alpha buff and gash ability if you have three it works that way for each three so if you have nine you have three alphas doing gash damage which ends up making them ideal for the rag bosses as it's not hard to get good allo saddles and the gash does a good deal of damage against golems
The Allosaurus is a pack-hunting theropod that's smaller but faster than Rex. When in packs of 3 or more, the highest level Allosaurus will become the pack leader, emitting a red aura and making it stronger in battle.~Steel Cookie 123
If you really think about it, these are SOOO underrated. Incredibly high damage and speed. A pack of 10 is easily better than a Giga. 3-4 ballista bolts, (lvl 29 btw) can make a Giga rage, and ballista bolts have a VERY long range, so... you’re dead if you’re riding it. Against a level 30 player. You see 10 Allos coming for you? Run for your ballista? 3-4 Allos dead, still 7 Allos killing you. Even rockets against 10 or so Allos? Crap. You’re still dead. They are so fast and can 20 shot ANY creature in the game if it’s an alpha. Yes, Titantos? Dead in 20 shots. (5% of the creatures health over time.) (Doesn’t work on bosses.) Compared to a Rex, an alpha Allo is arguably equal. Base stats of the Rex are 1100 health and 62 damage. Alpha Allo is 787.5 health and 52.5 damage. They have much faster DPS than Rexes and have better stamina, allowing for more overall damage. Not as much health, but still. To a wild Giga (level 1) with the alpha attack they deal 4000 damage. 4000!!!!!!!!!!