We can tell which monsters will drop a weapon. They are the ones that go on a rampage. I don't know why, but the correlation is obvious.
It seems that the monsters that go berserk are the ones that release weapons. Will you please defeat the Triceraclopes here in Forsaken Valley?
Please bring me the Banded Trident.
You have collected many of the weapons, now. We must seek the master weapon. Its is time to retun to Samurai Jack.
The Triceraclopese of the Forsaken Valley are displaying the same erratic behavior that we saw in the Dire Apes and Slizzards. I suspect this means that they are rip for harvesting a weapon.
Indeed, the beast dropped a weapon. Bring me that Banded Trident.