The fever spider body is a quest item used during the Rum Deal quest. It is obtained by killing a fever spider in the basement of the rum factory on Braindeath Island and is one of the ingredients of the unsanitary swill that the player must make during the quest. You can only get it during Rum Deal.
This cannot be used instead of a spider carcass to make pouches or on an arrow shaft or thatch spar to produce a spider on shaft or spider on stick.
- For an exhaustive list of all known sources for this item, see here.