This is the single greatest weapon in the early game. The second you find sand in ARK, make one of these. They break randomly like a spear, but seem to have better durability overall. They do crazy torpor damage and can be spammed over and over again to knock out even low-level rexes if you have enough of them. Just make sure to right-click to throw the boomerang instead of just hitting with it, which does a lot more damage and less torpor.