Golem: Necrophidius

The soft scrape of bone reveals the long, sinuous skeleton of a large snake, its head a humanoid skull with a snake's jaws.

Source: AD&D 2nd Edition Monstrous Manual. Originally appeared in AD&D 1E Fiend Folio

Silent assassins. Deadly protectors: Necrophidius are created for the sole purpose of eliminating a foe or guarding an important area or object. These Death Worms are golems that make no noise even as they slither across the dungeon floor. They have a macabre grace and can easily surprise a group of adventurers. Necrophidius is known for it's Dance of Death. An ability that can turn an encounter into a massacre with a few bad saves.

Combat: The Necrophidius is a Golem in AD&D 2nd Edition. It's a large creature and meant as a low level challenge. Although with it's special abilities it can also pose a threat to mid-level adventurers.

-Silence: Because it doesn't make noise the Necrophidius can surprise opponents with ease. The silence imposes a -2 to surprise rolls.

-Dance of Death: The Death Worm can sways it's body in a hypnotic dance. Anyone who observe the dance must save vs. spell or be hypnotized as the hypnotism spells. As you stand motionless the Death Worm can attack without hesitation.

-Paralysis: The Bite of the Necrophidius can paralyze an adventurer for 1d4 turns unless a save vs spell is made. 

Immunity: The Death Worm is an artificial creature and immune to mind-affecting abilities. Also immune to poison. Although it looks like an undead creature it is immune to being turned.

The Necrophidius is a dangerous foe. With two special abilities that can control the battlefield the Death Worm can be a deadly encounter.