Dragon-spell

The bewildering power in the gaze of a Dragon was able to sap the wills and control the minds of less powerful beings. Even a glance from a Dragon could make the effect felt, but one drawn into the stare of such a being would come entirely under its power. Once the Dragon had placed a victim under its power, the effects would last even when the Dragon itself was not present, though the spell could apparently be broken by the Dragon's death.

The most detailed accounts we have of this power come from tales of the Dragon Glaurung, who used his Dragon-spell in the service of his master, the Dark Lord Morgoth. Having defeated the armies of Nargothrond, Glaurung descended into that underground fortress and used his spell to capture the will of Túrin. The effect was to freeze his enemy in place while Glaurung used the power to present a twisted version of Túrin to himself, and then sending the warrior running into the wild in despairing pursuit of captured Finduilas.

Túrin's sister Niënor suffered a more extreme form of the Dragon-spell. Niënor came upon Glaurung unexpectedly, and her eyes were drawn into those of the Dragon, who used the spell to rob her entirely of her memories and identity. This loss persisted for several years (showing that the Dragon did not have to be present for the spell to work). It was not until long afterward that Túrin slew Glaurung, and with the Dragon's death, the Dragon-spell was lifted.¹

For its full effect to be felt, the Dragon would have to fix the gaze of its victim, and evidently the power of the spell was even greater if the Dragon knew that individual's name. Neither of these was essential, however, for the power of the Dragon-spell to be felt. When Bilbo Baggins was in the presence of Smaug, he could feel the spell impelling him to reveal himself, even though Smaug could not see him, and did not know who - or indeed what - he was. Bilbo was able to resist the compulsion, and wisely avoided revealing too much about himself or his purposes to Smaug.

There was possibly some connection between the Dragon-spell and the Dragon-sickness, another magical effect created by Dragons that could twist the minds of those who sought their treasure. While the Dragon-spell was purposefully exercised by a Dragon through its gaze, the Dragon-sickness was more passive in nature, causing those who came into contact with a Dragon's hoard to become greedy for gold and careless of others, much like the Dragon itself.