"The Curse of the Monolith" is a short story by American writers L. Sprague de Camp and Lin Carter, featuring the fictional sword and sorcery hero Conan of Cimmeria created by Robert E. Howard.
Shu sends Conan back to Turan with a formal letter of acceptance and provides him with a high noble of his own court, Duke Feng, to act as a guide and escort.
When they reach the site indicated by Feng, Conan sees a large burial mound with a black monolith of stone towering up into the night sky, the top of which is obscured by mist.
The duplicitous Feng then explains his true identity and purpose, and that the monolith is composed of a magnetic stone which exerted a force of attraction upon Conan's metal armor.
Struggling to escape, Conan eventually manages to cut the leather straps of his armour with a rusted dagger and tears himself free before the amoeba could devour him with its acidic pseudopods.