Husk of the pit
From Destinypedia, the Destiny wiki
husk of the pit. ah, damage from it is fairly good for a common weapon (138d). to obtain just simply kill blades of crota and then ( if it drops) it will pop into your inventory. to upgrade you need to kill 500 hive get 10 black wax idols + crotas bane rank 4 to get edion ally. to upgrade that, get it to the final upgrade + a crux of crota ( obtained very, very rarely from hard difficulty crotas end raid). then you have necrochasm!