The Thrall's Gate summons a pet Lil' Leonard which follows the player around. If the player gets too far from Lil' Leonard, he rushes towards the player on a cloud, passing through blocks.
Trivia[]
The item is a reference to Elder Scrolls. Lil' Leonard himself is a reference to Frost Atronachs, which are found in many daedric planes of Oblivion, including planes of minor princes who may or may not be depicted as a dragon, rendering the tooltip's validity questionable.