Necrophidius

The Necrophidius which is Greeky-geeky sciencey jargon for "Death Worm" is a bone-golem raised from a giant snake skeleton and a human skull. Its bite can cause paralysis but magical paralysis - not venomous. It can further do a snake dance to hypnotise opponents. It has "Average" intelligence so may be employed for assassinations.

This was the best monster submitted to Fiend Factory up to White Dwarf issue #15, if you asked its readers, which those editors did. Simon Tilbrook submitted it, which made it to #7, in time for Fiend Folio to recognise its awesome and include it. The Tome of Horrors gave them a 3e makeover.

White Dwarf #25 would post a "Guardian" variant: its spirit can leave its body and animate its petrified victims, one at a time. In its own body, it regenerates. Even more awesome; but TSR - burned by the dross in the 'Factory up to #13 - was ignoring those submissions so missed this one.