Stone of weight

A stone of weight or loadstone was an extraordinarily inconvenient cursed magical item.

Description
A loadstone appeared as if it were a harmless or even beneficial magical rock, such as a stone of good luck or stone of controlling earth elementals.

Powers
When the stone was carried or held in most situations, its powers were inactive. As soon as the bearer found themselves in need of rapid action, such as combat or any number of other life-and-death situations, they found themselves drastically slowed down and unable to complete any task quickly.

The stone resisted attempts to be rid of it, reappearing somewhere on the victim's body if it were destroyed or thrown away. It could only be removed by use of a dispel evil spell.