Fever spider body (only dropped during the Rum Deal quest)
Basement of Captain Braindeath's brewery on Braindeath Island.
"A bunch of legs, eyes and teeth."
Slayer level 42 is needed to kill this monster. Always wear Slayer gloves, or you'll get a disease which can only be cured with Relicym's balm. Its max hit is 4 (11 if you don't wear the gloves).