Wiki says: To tame it, you need brute force like a rock straight into its head.
Billy (tribe of billy) - lvl 2: Will my Journeyman slingshot work? I just spawned here and i was told it eats rocks! I have some in my pocket! I WILL TAME IT
It was a sunny day in the mountains I had just fought of some hyeanodons I was encumbered from collecting metal when I was walking threw pathway when suddenly dust clouded the sky and a massive stone figure appeared I tried to run to no avail because of my greed for metal suddenly a massive rock fley threw the air and I was dead.